~a ',y ~.•. ( - , 0 :/.1//)9. ~ ' sj

,I

~ " ."..J ~ \: <~ "to

-t, '~... ,3 '+,

.• Geotechnical Characterization of the Subsoilin KhulnaCity Corporation (KCC) Area

,

'J

•~--- ---------------- -~~-_l

.,~~fGT~ ' ',:!", ~A" /I!;~~-a'i!"'J ').\( - ," 0 ,,&:.+ :.,\(, J:'i: ',' -.:r.... .,.. ,.:J. ..... SJ ' b ' ,

',Y ~.•. \~~t :/.1//)9. ~ ' y

~ Sheikh Muhamma4 Ferdous

A thesis' submitted to the Department of Civil Engineering of

Bangladesh University of Engineering & Technology, Dhaka in partial

fulfilment of the requirement for the degree

of

MASTER OF SCIENCE IN CIVIL ENGINEERING

(GEOTECHNICAL)

, {""" '---. ----...........~ "':':- ~ ---~ -,0( j ,

~' "1111I1"!JI~~l~~!" 1111111 ' ;1 .~~: . -" " ~:.......- ~.- . -::..=~-----...=,- _ .• ---- ~ ••.

..:...----- •.•.• ~'k" •••. "l" •••.• •

Department of Civil EngineeringBANGLADESH UNIVERSITY OF ENGINEERING AND TECHNOLOGY

September, 2007".-,

,'.

~,',",,'••~-t rc-

"'1.-.I.

-I;

BANGLADESH UNIVERSITY OF ENGINEERING AND TECHNOLOGYDEPARTMENT OF CIVIL ENGINEERING

The thesis titled "Geotechnical Characterization of the Subsoil in Khulna City

Corporation (KCC) Area" submitted by Sheikh Muhammad Ferdous, Roll No:

040304202, Session: April 2003 has been accepted as satisfactory in partial fulfilment

of the requirement for the degree of Master of Science in Civil Engineering (Geotechnical)on September 29,2007.

BOARD OF EXAMINERS

::.

~~Dr. Abdul abbar KhanAssociate ProfessorDepartment of Civil Engineering.BUET, Dhaka-lOOO.

~ •Dr. Muhammad Z~ariaProfessor and HeadDepartment of Civil EngineeringBUET, Dhaka-J 000.

?

Dr. Abu SiddiqueProfessorDepartment of Civil EngineeringBUET, Dhaka-l 000

1n£J -JR~~~)')Dr. Mehedi Ahmed AnsaryProfessorDepartment of Civil EngineeringBUET, Dhaka-IOOO

rJJJDr. Md. Abul BasharProfessorDepartment of Civil EngineeringKUET, Khulna

September 200711

Chairman(Supervisor)

Member

Member

Member

Member'(External)

'-

..,I

DEDICATION

DEDICATED TO MY PARENTSAND

MY SWEET WIFE

iii

!~.

DECLARATION

It is hereby declared that except for the contents where specific references have been made to

the work of others, the study contained in this thesis are the result of investigation carried out

by the author under the supervision of Dr. Abdul Jabbar Khan, Associate Professor,

Department of Civil Engineering, Bangladesh University of Engineering and Technology.

No part of this thesis has been submitted to any other university or other educational

establishment for a degree, diploma or other qualifications (except for publication).

(Sheikh Muhammad Ferdous)

IV

~. ACKNOWLEDGEMENT

The author expresses his sincere gratitude to the supervisor Dr. Abdul Jabbar Khan, Associate

Professor, Department of Civil Engineering, Bangladesh University ,of Engineering and

Technology for his continuous guidance, sincere directions to analyze data and critical

review of foundation systems in light of practical experience from beginning to end of this

research study.

.~ ..

;-t,.o(

The author is likewise grateful to Syed Azizul Haq, P.Eng., Executive Engineer, PWD

Design Division-4, Purta Bhabon, Segun Bagicha, Dhaka for his encouragement and

support over the period of this research work.

v

~ ABSTRACT

Erratic soft subsoil deposits and presence of organic layer in the Khulna City Corporation

(KCC) area pose potential challenge to the design and construction of foundation for building

structures within the area. Therefore, it is essential to develop a general understanding of the

characteristics of the subsoil formation of the KCC area. In this study, an attempt has been

made to perform a systematic geotechnical investigation consisting of ,different field and

laboratory tests extending from South to North of the KCC area. Standard Penetration Test

(SPT) has been carried out at six selected locations in order to collect disturbed. and

undisturbed samples and also to record SPT blow counts. Laboratory investigations have

been performed in order to identify the index properties, shear strength properties and

'..- compressibility properties of different soil layers.

Field investigations and laboratory index test results reveal that the upper layer of north part

of the KCC area i.e. Goalkhali and Khalishpur consists of subsequent layers of elastic silt,

organic clay layer, elastic silt to silty clay and fat clay. On the other hand, upper layer of

south non-riverside area i.e. Chotta Boyra, Sonadanga and Farazipara area consists of fat clay

to clayey silt which is underlain by organic clay layer. This organic clay layer is followed by

elastic silt with fine sand layer which is underlain by silt with fine sand and. mica. The top

layer of south riverside area is predominantly clayey silt. Unlike other areas, no organic layer

exists below this top layer. The following layers of this part of the ;KCC area consist of

.'t- elastic silt underlain by silt with mica.

The natural moisture content as well as degree of saturation for both organic and inorganic

soil samples is high. Both SPT - N value and unconfined compressive strength of the upper

layer are low and it is difficult to draw any correlation between them. Unlike upper layer, the

type of soil below the organic layer can be classified as c-<t>type in which angle of internal

friction dominates. Measured angle of internal friction value corresponding to relative

density obtained by SPT -N value is low. The compressibility of inorganic clay and silt is

VI

•s -"

~,.JI&.----..-s;,~"

(

j'

moderate to high while the compressibility for orgamc clay layer is very high. The

coefficient of secondary compressibility is also high for both organic and inorganic layers.

Based on the geotechnical characteristics identified in this study, it is suggested that Rammed

aggregate pier (RAP) may be useful ground improvement technique for low to medium rise

buildings for both north and south part. Preloading with vertical drains may be considered to

be the suitable ground improvement technique for the north part i.e. Goalkhali andKhalishpur area.

Piled raft foundation system may be suitable for tall buildings where basement is required.

Commonly practiced piled foundation may be employed for buildings where basement is not

required or in situations where excavation is difficult.

VB

~V" CONTENTS" ----------------------------'1-

'C~">4

Page No.

DECLARATION

ACKNOWLEDGEMENT

ABSTRACT

TABLE OF CONTENTS

LIST OF FIGURES

LIST OF TABLES

NOTATIONS

CHAPTER 1 INTRODUCTION

•IV

V

VI

Vl11

XIV

XVl11

XXI

1

"

.. "I'1

1.1 GENERAL

1.2 LOCATION OF THE STUDY AREA

1.3 GEOLOGY OF THE STUDY AREA

1.4 BACKGROUND OF THE PRESENT RESEARCH

1.5 OBJECTIVES

1.6 ORGANIZATION OF THE THESIS

CHAPTER 2 LITERATURE REVIEW

2.1 GENERAL

2.2 AVAILABLE GEOTECHNICAL DATA

2.1.1 Index Properties

2.2.1.1 Organic Matter Content

2.2.1.2 Specific Gravity

Vlll

1

4

45

6

7

8

8

8

8

8

9

I ..

2.2.1.3 Natural Moisture Content

2.2.1.4 Degree of Saturation

2.2.1.5 Atterberg Limits

2.2.2 Shear Strength Properties

2.2.2.1 Shear Strength Properties and SPT -N Relationship

2.2.3 Consolidation Properties

2.2.3.1 Consolidation Index and Coefficient of Consolidation

2.2.3.2 Empirical Relations for Compression Index

2.2.3.3 Preconsolidation Pressure

2.2.3.4 Coefficient of Secondary Compression Index

2.3 GROUNDWATER TABLE

2.4 FOUNDATION SYSTEM FOR THE STUDY AREA

2.4.1 Theoretical Background of Buoyancy Raft Foundation

2.4.2 Case Study of Buoyancy Raft Foundation at Goalkhali Area

2.4.2.1 Geotechnical Data

2.4.2.2 Foundation System

2.4.2.3 Performance

2.4.3 Theoretical Background of Piled Raft Foundation System

2.4.4 Case Study of Piled Raft Foundation at Klang, Malaysia



2.4.2.3 Performance

2.4.5 Theoretical Background of Deep Pile Foundation

2.4.6 Case Study of Deep Pile Foundation at Sonadanga, Khulna



IX

Page No.

9

9

9

11

11

15

15

17

18

18

19

20

21

21

23

24

2425

25

28

2831

32

32

37

38

Page No.

\•• 2.5 GROUND IMPROVEMENT TECHNIQUES FOR THE STUDY AREA 392.5.1 Theoretical Background of Rammed Aggregate Pier (RAP) 392.5.2 Case Study of Rammed Aggregate Pier at Beaverton, USA 42

2.5.2.1 Geotechnical Data 422.5.2.2 Foundation System 422.5.2.3 Performance 43

2.5.3 Theoretical Background of Pre loading without Vertical Drain 44

2.5.4 Case Study of Pre loading without Vertical Drain 452.5.4.1 Geotechnical Data 45

2.5.4.2 Foundation System 47

'1' 2.5.4.3 Performance 47

2.5.5 Theoretical Background of Pre loading with Vertical Drain 48

2.5.6 Case Study of Preloading with Vertical Drain 50

2.5.7 Cut and Replacement Method for Foundation in Khulna 51

University Building

2.5.7.1 Geotechnical Data 51


2.5.7.3 Performance 51

2.5.8 Mattress Foundation for Boy's Hostel Building in Khulna 55

Medical College Area

,,;, .t., 2.5.8.1 Geotechnical Data 55.~


2.5.8.3 Predicted Performance 58

2.5.9 Shallow Foundation Accommodating Large Settlement

2.5.9.1 Geotechnical Data'


2.5.8.3 Predicted Performance

x

59

59

59

62

CHAPTER 3 GEOTECHNICAL INVESTIGATION PROGRAME

3.1 GENERAL

3.2 FIELD INVESTIGATIONS

3.2.1 Standard Penetration Test

3.3 GEOTECHNICAL LABORATORY INVESTIGATIONS

CHAPTER 4 TEST RESULTS AND DISCUSSIONS

I

Page No. ' iI, ,I

63 tt;

63

63

63

66

70

4.1 GENERAL 704.2 IDENTIFICATION OF SUB-SOIL FORMATION 70

~: 4.2.1 Identification of Subsoil in North Part 724.2.2 Identification of Subsoil in South Non-riverside Area 724.2.3 Identification of Subsoil in South Riverside Area 72

4.3 DETERMINATION OF REDUCED LEVELS 734.4 GPS POSITIONS 744.5 LABORATORY TEST RESULTS AND DISCUSSIONS 76

4.5.1 Grain Size Distribution 76

4.5.2 Organic Matter Content 78

4.5.3 Specific Gravity 79

4.5.4 Natural Water Content and Degree of Saturation 80

4.5.5 Atterberg Limits 82-'''- 4.5.6 Shear Strength Characteristics 86

4.5.7 Compressibility Characteristics 91

4.5.7.1 Compression Index 914.5.7.2 Secondary Compression Index 944.5.7.3 Coefficient of Consolidation 964.5.7.4 Coefficient of Volume Compressibility 96

4.5.7.5 Coefficient of Permeability 96

Xl

CHAPTER 5 SUGGESTED GROUND IMPROVEMENT TECHNIQUES

AND FOUNDATION SYSTEMS FOR THE KCC AREA

Page No.

98

5.1 GENERAL 98

5.2 GROUND IMPROVEMENT TECHNIQUES 98

5.2.1 Preloading with Vertical Drains 99

5.2.2 Rammed Aggregate Pier (RAP) 100

5.3 FOUNDATION SYSTEMS 102

5.3.1 Buoyancy Raft:Foundation System 102

'-f 5.3.2 Piled Raft Foundation 102

5.3.3 Pile Foundation 102

CHAPTER 6 CONCLUSIONS AND RECOMMENDATIONS

6.1 GENERAL

104

104

6.2 THE GEOTECHNICAL CHARACTERISTICS OF THE KCC 104

AREA SOIL

6.3 GROUND IMPROVEMENT TECHNIQUES 106

6.4 FOUNDATION SYSTEMS 106

6.5 RECOMMENDATIONS FOR FUTURE STUDY 107

REFERENCES:

Xll

108

'f.-'..: APPENDICES:

A : Record of Subsurface Exploration

B : Grain Size Distribution Results

C : Unconfined Compressive Strength Test Results

D : Direct Shear Test Results

E : Consolidation Test Results

F : Calculation of Different Types of Foundation Systems

Xlll

Page No

114

115

128

147

153

158

167

LIST OF FIGURES'.

\.-r. xv

Page No.

",. Figure 2.25: Boring logs at coastal plain 46(after Stamatopoulos and Kotzias, 1985)

Figure 2.26: Standard penetration resistance versus elevation 46(after Stamatopoulos and Kotzias, 1985)

Figure 2.27: Pattern of equidistant drains (after Stamatopoulos and Kotzias, 481985)

Figure 2.28: Vacuum technique used at Hazawa station, Japanese national 49railway (after Lee et aI., 1993)

Figure 2.29: Typical borelog at Khulna University campus 52(after Razzaque and Alamgir, 1999)

Figure 2.30: Mat foundation on engineered fill for academic building-I at 53Khulna University area (after Razzaque and Alamgir, 1999)

r-~Figure 2.31: Observed settlements with respect to time of Academic 53•••Building-I at Khulna University(after Razzaque and Alamgir, 1999)

Figure 2.32: Typical bore log at Khulna Medical College 55(after Kabir et aI., 1997)

Figure 2.33: Detail of column footing on mattress 56(after Kabir et aI., 1997)

Figure 2.34: Details of wall footing on mattress (after Kabir et aI., 1997) 56

Figure 2.35: Comparison of deflections of wall footing 58(after Kabir et aI., 1997)

.~.,. Figure 2.36: Comparison of deflections of column footing 58'. (after Kabir et aI., 1997)

Figure 2.37: Compacted was placed on a 2-ft thick layer of crushed stone 60(after Wu & Scheessele, 1982)

Figure 2.38: " T " shaped grade beams footings 61(after Wu & Scheessele, 1982)

Figure 3.1: Map ofKhulna City Corporation (KCC) area and borehole 64locations.

XVI

,.~(~!~.:.(.- D.

XVll

Or LIST OF TABLES••••Page No.

Table 2.1: Percent of organic matter content in different depths and 8borehole locations at Khulna University Area (after Razzaqueand Alamgir, 1999).

Table 2.2: Atterberg limits with respect to depth at Sonadanga and 10Goalkhali area (after Hossain and Rahman, 2005).

Table 2.3: Correlations between consistency, N-value and qu of cohesive 12inorganic fine-grained soils (after Terzaghi and Peck, 1948 & '1967)

"-.<" Table 2.4: Correlations between N-Value and unconfined compressive 12" strength for different soil types (after Sowers, 1953 & 1962).

Table 2.5: Typical borehole data of SPT -N value and qu(kPa) at 14Goalkhali area (after Hossain and Rahman, 2005).

Table 2.6: Compressibility characteristics with respect to compression 16index and liquid limit

Table 2.7: Primary consolidation parameters of fine-grained soils 16(Serajuddin, 1998)

Table 2.8: Summary of consolidation parameters at Khulna Medical 16College (after BRTC, 2003).

Table 2.9: Equations used to calculate Cc for inorganic cohesive soil 17...y samples (after Bowles, 1997),

Table 2.10: Approximate range of preconsolidation values of clays and 18silts ofKhulna (after Serajuddin, 1998).

Table 2.11: A guide to values of the coefficient of secondary 19consolidation, Ca (after Lee et aI., 1983)

Table 2.12: Long term S case shear strength of alluvial soil (after Design 33of Pile Foundations, 1994)

XVlll

Page No.

•• Table 2.13: Common values of lateral earth pressure coefficient, k (after 36. ' Design of Pile Foundations, 1994).t<:~_-: ___

Table 2.14: Values of shaft friction angles, 8 (after Design of Pile 36Foundations, 1994)

Table 2.15: Records of foundation settlement for Academic Building-I 54,(after Razzaque and Alamgir, 1999).

Table 2.16: Elastic modulii for the aggregates and clay layers (after Kabir 57et al., 1997).

Table 2.17: Modulus of subgrade reaction for wall and column footings 58(after Kabir et al., 1997).

Table 3.1: List of undisturbed samples collected during SPT test 65

-.-< Table 3.2: Summary of disturbed samples, depth and the name of 67laboratory test.

Table 3.3: Summary of undisturbed samples, depth and the name of 68laboratory test

Table 3.4: Name of the laboratory tests and the standards followed 69

Table 4.1: Latitude and longitude of boreholes points 74

Table 4.2: Summary of grain size distribution of inorganic Soils 77

Table 4.3: Summary of organic matter content at different borehole 78locations.

.~~' Table 4.4: Summary of the values of specific gravity of different types of 79soil samples

Table 4.5: Summary of natural moisture content and degree of saturation 81

Table 4.6: Summary of Atterberg limits 83

Table 4.7: Summary of qu and SPT -N value of inorganic cohesive soils 88of different depth and different borehole locations.

Table 4.8: Summary of shear strength parameters 90

XIX

I

JJ

xx

NOTATIONS

Symbol Description

Wn Natural water content---------

WL Liquid limit

wp Plastic limit----_._--_ .._---------

Ip Plasticity Index--- ..-

qu Unconfined compressive strength._---_ .._._------

N Standard Penetration Resistance

f Correlation factors

eo Initial void ratio

Cc Compression index--------_0 - -- ---_.- --,----,

Cv Coefficient of consolidation---- --

w Natural moisture content----.

p'C Maximum preconsolidation pressure-

p'a Effective pressure._-

CM Casagrande method_._-

SM Square root time fitting method._-----

OCR Over consolidation ratio

CR Virgin compression ratio

Gs Specific gravity

xxi

'. '.

>--.}- - ,..)

Symbol ~ Description..

S Degree of saturation_._---------------------- 1------- --O.C Organic matter content.._-_ ..•..~---_..._-~-------_._--_._._---.._- .._-----~.•...-_._------------_. __ .__ .,_.__ ._._--_ ..•,--_._~--...__._._.~-_._-----_..•_----- --

C Cohesion

 Angle of internal friction--.

ca Coefficient of secondary consolidation

GPS Global positioning system- -

Cll Undrained cohesion--_._----------_._------------ -----------_ .._-.- .._---------'------

Ef Percentage of strain at failure

'Yd Dry density

Dr Relative density

kgp Geopier stiffness modulus

kp Stiffness of pile group_. -----kc Stiffness of raft

-

~ , acp Average interaction coefficient between pile and raft

kf Stiffness of piled-raft--- -- --

Pc Load carried by raft------- - ---_.-

Pp Load carried by pile group---'~-- -

A Pile stiffness ratio-_._--_. -- -------

v Poisson's ratio

~ Ration of end bearing--

p Soil modulus .., Radius of influence of pile

XXI1

•

I-. ~

\r., CHAPTER 1

INTRODUCTION

1.1 GENERAL

The Khulna City Corporation (KCC) area standing on the bank of Rupsha river occupies

most of the northern part of the world's largest mangrove Sundarban forest It is believed that

once upon a time Sundarban forest was extended up to the KCC area. In course of time,

.,~ sedimentation and decomposition of wood and plant had contributed to build up organic soft

clay deposit in the KCC area, Morgan and McIntire (1959).

Presently, 43.0 sq km KCC area comprises the central part of Khulna Divisional City. Due to

excellent communication, its ,current population of 1.22 million is increasing by leaps and

bounds (Bangladesh Bureau of Statistics, 2001). To meet the demand of these people, more

industrial, commercial buildings, ports, hospitals, universities, colleges, schools and housing

facilities are being built up rapidly. Moreover, in order to maximize the benefit from

important city area, tall buildings with or without basement for commercial purposes and

medium rise apartment residential buildings are gaining popularity.

The traditional practice of foundation system for low rise to high rise building structure is to

use deep foundation. Mat foundations on improved ground have been used for a number of

four storey residential buildings. Improved layer was created by compaction of brick chips

and local sands and use of geotextile over the compacted layer. Unfortunately, some of these

mat foundations have been reported to suffer excessive total and differential settlements,

Figure 1.1 to 1.4.

1

--¥\

J1-~I.~.

,,'

Figure 1.1 Shear crack in the wall due to uneven settlement of a.

one storey building at Khulna Medical College.

Figure 1.2 Tilting and differential settlement of a four storey residential

building at Khulna Medical College.

2

Figure 1.3 Excessive foundation settlement at Boys' Hostel Building

of Khulna Medical College.

Figure 1.4 Differential settlement at expansion joint of Boys' Hostel

Building of Khulna Medical College.

3

•.

... ..~~

),, .

1.2 LOCATION OF THE STUDYAREA

Geologically, southwest part of Bangladesh is underlain by deltaic deposits of the mighty

Ganges River. These deltaic deposits are the deposited on the active delta, which is defined

as the South of the Ganges River and mostly west of the Meghna estuary. South part of the

project area is the tidal area. The study area is covered by either active, inactive or tidal delta

region, Figure 1.5 (Alam et aI., 1990). The geographical position of the Khulna City

Corporation (KCC) area lies between 22° 48' and 22° 52' north latitude and between 89° 31'

and 89° 34' east longitude (SPARRSO, 1999), Figure 1.6.

Figure 1.5 Geological map of Bangladesh(after Alam et aI., 1990).

Figure 1.6 Khulna City Corporation areaboundary (after SPARRSO, 1999).

1.3 GEOLOGY OF THE STUDYAREA

The study area is crossed by parallel south~southeast distributary channels. The ground water

lies either at the surface or at about 1.0 m below the existing ground level during rainy season

4

and dry season, respectively. Historically stable delta front and presence of artifacts found

below water table (Morgan and McIntire, 1959) suggest that large areas of the middle and

lower delta area are subsiding. According to the study of Morgan and McIntire (1959),

Bangladesh is filled with sediments of Tertiary to Quaternary age and recent flood plain and

piedmont alluvium, which occupies roughly seventy percent of the total land area of

Bangladesh. Moreover, the sediments of Bangladesh is divided into two major tectonic units,

the Precambrian platform in the northeast and the Bengal Foredeep in the southeast separated

by Kolkata-Mymensingh Hinge Line. The thickness of the sedim~ntary cover on the

basement is increasing towards southeast and the area affects by the settlement due to

consolidation of the sediments (Siddique et aI., 2002). Soft soil in the study area is mainly

available in alluvial flood plain deposits, depression deposits and tidal plain deposits. The

soft soil is comprised of unconsolidated to normally consolidated clays and silt containing

organic materials. The alluvial flood plain deposit consists of silts and silty clays with silt

predominating. Fine sand with mica abounds at greater depth. The depression deposits

contain organic clay deposits overlying clay at depth and estuarine and tidal floodplain

deposits is silt and silty clays; organic soils close to the surface in some places (Siddique et

aI., 2002). The average elevation is +2.75 m with respect to the mean sea level (Khulna

Master Plan, 2001) and the land gradient is approximately 1 meter per 20 kilometers (Alam

et aI., 1990).

1.4 BACKGROUND OF THE PRESENT RESEARCH

~. The upper 3 to 3.5 m thick layer of the KCC area consists of silty clay, which is underlain by

deep black organic clay of 1.0 to 1.25 m thick layer. Below this organic clay, there exists a

clayey silt layer up to the depth of 10 to 14.5 m. Silt with fine sand and mica or fine sand

with trace of organic matter and mica are encountered as the depth increases. It has been

reported by many researchers, viz. Das (2005), Bearing capacity of soils (1994), Lee et ai.

(1983) that due to the presence of different layers 'of silty clay, organic layer and fine sand

with organic matter and mica which may contribute to punching or local shear failure, special

attention should be paid while using the classical methods of bearing capacity and settlement

,..5

analysis for shallow as well as deep foundations. Though the KCC area is one of the oldest

).. developed areas of Khulna district, only a few geotechnical field and laboratory test data of

"'. this area are currently available. These too are not adequate for geotechnical characterization

of the subsoil within the area. Moreover, lack of proper understanding of the foundation

system may lead to foundation failure of several buildings in the area. Therefore, it is

essential to determine a systematic geotechnical study and the appropriate foundation systemfor the KCC area.

1.5 OBJECTIVES

The objectives of the present study are as follows:

.\... -.- ..,..,

(1) To analyze the available field and laboratory data.

(2) To execute soil exploration programme at some selected locations within the studyarea.

(3) To develop soil profile of the study area

(4) To determine the geotechnical properties of the collected samples.

(5) To suggest the best suited soil improvement techniques and efficient foundation

systems for the building structures within the study area.

6

1.6 ORGANIZATION OF THE THESIS

The research work conducted for achieving the stated objective is presented in several

chapters of this thesis. The thesis consists of six chapters. A brief discussion of each chapteris as follows.

Chapter One describes location and geology of the study area, background of this study andthe research objectives.

Chapter Two discusses the geotechnical properties and foundation systems for building

structures within the study area. Geotechnical properties include index properties, shear

strength properties and compressibility properties. The foundation systems include buoyancy

.::.r raft foundation, piled raft foundation and pile foundation. Ground improvement techniques

are rammed aggregate pier, preloading without vertical drain, preloa:dingwith vertical drain,

cut and replacement method and foundation accommodating large settlement.

Chapter Three consists of geotechnical investigation programme. Field investigation

programme includes determination of GPS location of boreholes and performance of

Standard Penetration Tests at different locations. Laboratory investigation programme

describing the name of laboratory tests for disturbed and undisturbed soil samples and the

relevant standard test method is also given in this chapter.

Chapter Four includes the identification of subsoil formation of the study area. A soil prolile

.~ is presented with respect to the Survey of Bangladesh (SoB) benchmark along north south

section of the study area. The shear strength and compressibility panpneters are shown with

graphs and tables.

Chapter Five contains suggested ground improvement techniques and foundation system for

the study area.

Chapter Six includes the conclusions and recommendations on the basis of the present study.

7

CHAPTER 2

.~\ .

LITERATURE REVIEW

2.1 GENERAL

This chapter contains a summary of the available geotechnical data of the KCC area and

also a detail presentation of case studies of different types of foundation systems and

ground improvement techniques employed in this area or alike.

2.2 AVAILABLE GEOTECHNICAL DATA

The available geotechnical data of the study area i.e., the index properties, shear strength'

properties and compressibility properties obtained from different sources are presented in

the following subsections.

2.2.1 Index Properties

2.1.1.1 Organic Matter Content

Razzaque and Alamgir (1999) reported that the organic matter content at different depths

of boreholes at Gollahmari (Khulna University) area varies from 3.27 % to 49.81 %,

Table 2.1.

Table 2.1 Percent of organic matter content in different depths and borehole locations at

-1. Khulna University area (after Razzaque and Alamgir, 1999)<',

Borehole No Depth (m) Per cent ratio of organic soil (dry weight)

1 1.37 -1.83 3.27'.

1 2.89 - 3.35 42.79

1 5.97 - 6.40 2.49

3 2.44 - 2.89 49.81

3 5.79 - 5.94 5.87

Munshi (2003) showed that organic matter content remains in the range of 5 % to 30 %

up to the depth of 12 m at Mollahat-Noapara Road Section in Bagerhat district. The

A. Bagerhat district is adjacent to the study area} '.

2.2.1.2 Spedfic Gravity

Bowles (1997) described that specific gravity of the inorganic clay (CL, CH, CH/CL and

CL-ML) and inorganic silt (ML, MH, ML/CL) may vary from 2.68 to 2.75 and from 2.60

to 2.68, respectively. Bowles (1978) also reported that specific gravity of organic clay is

variable but may be below 2.0. Shafiullah and Ali (BRTC, 2003) described that the

specific gravity of organic clay and clayey silt layers remain in the range of 2.14 to 2.49

and 2.74 to 2.78, respectively at Chota Boyra (Khulna Medical College) located within

the KCC area.

2.2.1.3 Natural Moisture Content

Razzaque and Alamgir (1999) reported that natural moisture content at Gollahmari

(Khulna University) area remains in the range 0£40 % to 50 % for inorganic fine-grained

soil and may be as high as 134 % for organic clay soil. Siddique et al. (2002) also

reported the moisture content within the upper 6 m in Khulna University area to he as

high as 400 %; That moisture content of organic layer at Chota Boyra (Khulna Medical

College) area was found to be in the range of 117.90 % to 221.80 % while the moisture

content of the clayey silt layer was found to be in the range of 34.60 % to 39.90 %,

(BRTC, 2003).

2.2.1.4 Degree of Saturation

ShafiuUah and Ali (BRTC, 2003) reported that the degree of saturation of organic clay,

soft inorganic clay and silty soil at Chota Boyra (Khulna Medical College) area were in

the range of 81.80 % to 100.00 %, 81.20 % to 96.30 % and 93.50 % to 97.0 %,

respectively.

2.2.1.5 Atterberg Limits

Consultancy Research and Testing Services of Department of Civil Engineering of

Khulna University of Engineering and Technology (KUET) explored the subsoil

condition of Sonadanga Thana Residential project and at Goalkhali Sheikh Abu Naser

9

Hospital Projects. According to these, the moisture content of organic layer remains in

the range of89 % to 370.0 % while liquid limit and plasticity index vary in the range of

\-' 80.0 % to 352 % and 24.44 % to 181.0 %, respectively. Moreover, in case of very soft

clay layer the moisture content, liquid limit and plasticity index remains in the range of

41.16 % to 53.38 %,52.80 % to 82.30 % and 16.00 % to 26.88 %, respectively. Beside

these, in case of silty clay soil the moisture content, liquid limit and plasticity index are

reported to be in the range of 44.00 % to 67.92 %, 31.10 % to 56.70 % and 7.00 % to

17.95 %, respectively, Table 2.2. A graphical presentation of relationship between natural

moisture content, liquid limit and plasticity index with depth is shown in Figure 2.1.

Table 2.2 Atterberg limits with respect to depth at Sonadanga and Goalkhali area (after

Hossain and Rahman, 2005)

Location Soil type Depth (m) . oon(%) ooL(%) oop(%) lp(%)

Soft clay 1.50 42.00 82.30 57.20 25.10

3.05 89.00 352.00 171.00 181.00Organic soil

4.57 370.00 87.20 55.10 32.10

Sonadanga 9.14 45.00 32.00 25.00 7.00

10.67 44.00 31.10 22.00 9.10Silty clay

12.19 44.00 37.40 28.30 9.10

13.72 46.00 39.70 30.80 8.90

1.52 41.16 52.80 25.92 26.88Soft clay

9.15 53.38 56.00 40.00 16.00Goalkhali

Organic soil 3.05 107.12 80.00 55.56 24.44

Silty clay 16.77 67.92 56.70 38.75 17.95

10

150 200 250 300 350 400

<On (0/0 ), WI. (% ), Wp (0/0 )

50 . 100

-<>-. A-.D

• .-<> 0

-<>- *-0 .-I

'O-j[]-.'

~-.1J-.

~-----.ca

~--'OI

I

o0.0

15.0-1------• wn 0 Wl • Wp <> Ip---------------------

...l/'..

,~ ~'

1.5

3.0

4.5

.-... 6.0E--..c 7.5.•...C-O)0 9.0

10.5X' 12.0

13.5

Figure 2.1 Natural moisture content and Atterberg limits with respect to depth at

Sonadanga area (after Hossain and Rahman, 2005).

2.2.2 Shear Strength Properties

2.2.2.1 Shear Strength Properties and SPT-N Relationship

"1' The approximate correlation among SPT- N value and unconfined compressive strength,

qu for cohesive soils as suggested by Terzaghi and Peck (1948 & 1967) is

qu =f. N (kPa)

where, f = 12.50 for very soft to soft clay

= 13.33 for the medium stiff to hard clay.

On the basis of this, the consistency of clayey silts may be described as shown in

Table 2.3.

11

Table 2.3 Correlations between consistency, N-value and qu of cohesive inorganic fine-

grained soils (after Terzaghi and Peck, 1967)

Consistency N-value Unconfined compressive strength, qu (kPa)*

Very soft 0-2 <25

Soft 2-4 25-50

Medium stiff 4-8 50-100

Stiff 8-15 100-200

Very stiff 15-30 200-400

Hard > 30 >400

*Terzaghl and Peck (1967) used the unit in ton/sq. ft. which is converted here to kPa,assuming 1 ton/sq. ft. = 100 kPa

)t" The correlation between N and qu as obtained by Sowers (1953 and 1962) for cohesive

soils are presented in Table 2.4 and the average values of f range from 6.7 to 24.

Table 2.4 Correlations between N-Value and unconfined compressive strength for

different soil types (after Sowers, 1953 and 1962)

Soil typesStrength in kPa

Minimum Average Maximum

Highly plastic inorganic clay 14.4 N 24N 33.6N

Medium to low plastic clay.

9.6N 14.4 N 19.2N

Plastic silts, clays with failure planes 4.8N 6.7N 9.6N ISanglerat (1972) proposes the following relationships between N and qu for different soil

types with the values of f ranging from 13.33 to 25.0.

For clay, qu= 25 N kPa

For silty clay, qu= 20 N kPa

For silty sandy soil, qu= 13.33 N kPa

Murthy (1993) investigated the relationship between N and qu for the preconsolidated

silty clay encountered at Farakka in West Bengal, India. The moisture content of the soils

12

was close to the plastic limit, which for the soils varied from 30 to 40 percent, and the

liquid limit from 50 to 100 percent with the preconsolidation ratio in the order of 5. It has

~ been mentioned that there was a considerable scatter of test results and the relationship\

between quand N showsqu =10 to 20 N (kPa).

From a study (Serajuddin ~d Chowdhury, 1996) qu against N-values of the morganic

clay or silty clay layers measured by locally manufactured standard penetration test

equipment and local procedure of pulling and releasing the drop weight by a crew of

labours has indicated that quof saturated cohesive clay and silt layers can be estimated by

using the plasticity characteristics of the cohesive clay and silt deposits occurring in

different areas of Bangladesh.

The correlation factors are as follows:

(a) f =16 for clays and silts of high plasticity with WL~ 51 %

(b) f =15 for clays and silts of medium plasticity with WL = 36-50 %(c) f =13 for clays and silts oflow plasticity with WL:$ 35 %

Consultancy Research and Testing Services of KUET explored and reported the subsoil

condition of Sonadanga Thana residential project and at Goalkhali 'Sheikh Abu Naser

Hospital Projects. Table 2.5 and Figure 2.2 are the presentation of particular borehole

data at Goalkhali area Moreover, the relationship between SPT-N value and unconfined

compressive strength, qu (kPa) for different types of soil layers is shown in Figure 2.3.

13rj. ..!

,"

Table 2.5 Typical borehole data of SPT-N value and qu (kPa) at Goalkhali area.*, (after Hossain and Rahman, 2005)

Location BHNo. Depth (m) Soil type N value (field) qu (kPa)

1.52 Soft clay 2 66.33

3.05 Organic clay 4 11.53

4.57 Clay with trace 6 20.30silt

6.10 4 9.73Goalkhali 2

7.62 4 32.93

10.67 2 18.93

12.19 Silty clay 4 53.78

18.29 Clay with trace 5 12.96silt

-qu-o-Nvalue

10 20 3) 40 50 00 70 00

II

63.33I

1

I32.00I

00.0

3.0

6.0-.5.. 9.0.c:-~120

, 0-"(

15.0

1aO

21.0

I

Figure 2.2 SPT-N value and qu (kPa) with respect to depth at Goalkhali (after

Hossain and Rahman, 2005)

.. "

14

I•II•Ir * 1• •I II I I •

~

.1• • II • X

*• I• 1I ~

T "':'" I

*I, i •i I I

100\

."'.80

- 00coQ.JIl::-::::J

40C"

20

o1 2 3 456 7

SPT- N value (field)

8 9 10

I • Q-gjmic clay • Gay wilh trace sih • Soft c1ay XSiltyc1ay I

Figure 2.3 SPT-N value and qu (kPa) of different soil layers at Goalkhali

and Sonadanga area.

It can be concluded that the relationship between qu and N is not straightforward. Rather,

the relationship is very scattered in nature and it cannot be expressed by a single

correlation factor like uniform soil layer.

---( 2.2.3 Consolidation Properties

2.2.3.1 Compression Index and Coefficient of Consolidation

Compressibility characteristics can be termed as low, moderate and high. Table 2.6 can be

used to describe the compressibility with respect to compression index and liquid limit.

Consolidation test data of fine-grained soils of southwest zone of Bangladesh for

estimation of primary consolidation settlement are summarized in Table 2.7 (Serajuddin,

1998).

,c'"i~'

15

Table 2.6 Compressibility characteristics with respect to compression index and liquid

limit

Compressibility term Compression index Liquid limit (%)

Low 0-0.19 0-30

Moderate 0.20 - 0.39 31 ~ 50

High > 0.40 >50

Table 2.7 Primary consolidation parameters of fine-grained soils (Serajuddin, 1998)

Zone Depth USCS wn eo Cc Cv(m) (%) (m2/yr)

South-3.5-9.5 CL,ML,CH 24-47 0.706-1.32 0.080-0.520 1.73 - 100.91West

The consolidation parameters of the soil samples at Khulna Medical College (KMC) area

are summarized in Table 2.8.

Table 2.8 Summary of consolidation parameters at Khulna Medical College (after BRTC,

2003)

BH No Depth (m) w(%) eo Cc R=CJ(1+eo) Cy (m2/yr)

1 6.75 36.4 1.116 0.231 0.11 41- 65

1 8 34.6 0.98 0.176 0.09

2 4.8 58.9 1.703 0.529 0.20

2 8 39.9 1.23 0.293 0.13

3 4.8 221.8 5.79 2.97 0.44 3 -139

3 8 38.1 1.289 0.301 0.13 18 -252

4 4.8 117.9 2.92 1.201 0.31 2;6 - 8.6

4 8 39.4 1.16 0.245 0.11 50 - 370

From Table 2.8, it can be found that the moisture content, Wn. initial void ratio, eo;

compression index, Cc, compression ratio, R and coefficient of volume compressibility,

Cv remains in the range of 34.6 % to 221.80 %, 0.98 to 5.79, 0.18 to 2.97, 0.09 to 0.44

16

and 2.6-8.6 to 50-370 m2/yr, respectively. Comparing the obtained compression index,

Cc with that of shown in Table 2.6, it can be found that the upper 8.0 m depth layer at

0'" Khulna Medical College area shows moderate to high compressibility.

2.2.3.2 Empirical Relations for Compression Index

The compression index (Cc) of compressible clays and silts has some empirical relations

with liquid limit (ooL>,initial void ratio (eo) and natural moisture content (000), Serajuddin

and Ahmed (1967) correlated Cc with ooLand eo of a large number of undisturbed plastic

silts and clay soil samples of different areas of Bangladesh and obtained the following

empirical equations:

Cc =0.0078(ooL- 14 %)

Cc =OA4(eo- 0.30)

Another correlation study (Serajuddin and Ahmed, 1982) with additional test data from

fine-grained soils occurring within about 7 m from the ground surface of different areas °

of the country suggested the relationship:

Cc =0.47(eo- 0.46) with a correlation coefficient of 0.77

Virgin compression index, Cc can be calculated through different soil parameters such as

liquid limit, natural moisture content, initial void ratio and plasticity index. The

relationships given by different researchers are shown in the Table 2.9.

Table 2.9 Equations used to calculate Cc for inorganic cohesive soil samples (after

Bowles, 1997)

Compression Index, Cc Comments Source! Referenceo.

Cc=0.009(WL- 10) Clay Terzhaghi and Peek (1%7)

Cc=1.15(eo- 0.35) All clays Nishida (1956)

Cc= 0.009 WN+ 0.005 WL All clays Koppula (1986)

Cc= 0.046+ 0.0104 Ip Best for Ip < 50 % Nakase et a!. (1998)

Cc=0.37(eo+0.003 wL+0.OO04wo-0.34) 678 data points Azzouz et a!. (1976)

Cc = -0.156+ OAlleo+ 0.00058 WL 62 data pointsAl-Khafaji and Andersland

(1992)

17

'Ii...••,,

2.2.3.3 Preconsolidation Pressure

Analysis of consolidation parameters including effective overburden pressure (p' 0) and

estimated past maximum preconsolidation pressure (p' c) indicate that the clay and silt soil

strata are predominantly normally consolidated in Khulna area. But slightly moderate

overconsolidated clay and silt layers seem to exist in the southwest zone of Bangladesh,

Table 2.10.

Table 2.10 Approximate range of preconsolidation values of clays and silts of Khulna

(after Serajuddin, 1998)

Locationoon(%) ooL Ip p'C(kN/m2

) p'a OCR

CM SM (kN/m:l) CM SM

Khulna 1.78-32-53 35-60 11-29 98-175 98-120 36-100 1.75-438

around 2.18

Where CM and SM are the Casagrande Method and Square Root Method, respectively.

2.2.3.4 Coefficient of Secondary Compression Index (CJ

Secondary compression and creep are time-dependent deformations that appear .to occur

at essentially constant effective stress with negligible change in pore water pressure.

Secondary compression and creep may be a dispersion process in the soil structure

causing particle movement and they may be associated with electrochemical reactions

and flocculation. In some field situations secondary compression is more important than

primary compression. When soft soil deposits is preloaded or surcharged, the subsequent

primary settlements are essentially eliminated, and significant settlements occurs over the

economic life of the structure due to secondary compression of the soil (Lee et aI., 1983).

Cn can be estimated directly from 1D-consolidation test or it can be estimated from

indirect relations. The value of Cn for a variety of different types of soil is shown in

Table 2.11. Cn will in general increase with time if the effective overburden pressure, p' 0

is less than a preconsolidation pressure, p'C. For p' a greater than P'C,Cn will decrease

with time (Settlement analysis, 1994). A first approximation of Cn is O.OOOloon for 10 <

OOn < 3000 where OOn is natural water content in percent NAVFAC (1982).

IR

Ladd (l967) suggested that, for N. C. soils,

~, CIX (%);::: (4- 6) x CR

Where virgin compression ratio, CR=Cc/{l+eo).

Table 2.11 A guide to values of the coefficient of secondary consolidation, CIX(after Lee

et al., 1983)

Soil type CIX Reference

N.C. clays 0.005 -0.02 Ladd, 1967

N.C. alluvial clays.

1% organic content 0.003 Matsuo and Kamon, 1975

5 % organic content 0.001

N.C. clay Yamanouchi et aI., 1978

o % organic content 0.004 '.

9 % organic content 0.008

17% organic content 0.02

0, C. clays (0. C. R. > 2 ) < 0.001 Ladd,1967

Peat 0.02-0.10 Yasuhara and Takenaka,1977

*For a consolidation stress of 800 kPa and 1600 kPa,

2.3 GROUNDWATER TABLE

The weekly recorded ground water table data were obtained from BWDB for the study

area. On the basis of these data it is found that at Chota Boyra, north part of the study

area, the ground water table varies from 2.75 to 3.75 m. Therefore, the average annual

ground water table in the north part remains 3.25 m below EGL. On the other hand, at

Shipyard road, Rupsha- south part of the project area, the ground water table varies from

1.0 to 2.25 m. So, the average annual ground water table in the south part lies at 1.63 m

below EGL. The weekly ground water table data are shown in Figure 2.4. Therefore, it

can be concluded that the ground water table in the south part is very close to the ground

surface in comparison with north part,

19

1-0ct-00 28-Jul-01 24-May-02 2Q-Mar-03 14-Jan-04 9-Nov-040.0

- Shipyard Road (South part)

SoB benchmark is + 0.46 m with

respect to BWDB datum, BWDB.0.5

1.0

- 1.5E'-'"Q) 2.0>Q)....J'U 2.5Q)0:::::I 3.0'UQ)0:::

)r-3.5

4.0

4.5- Boyra (North part)

Figure 2.4 Weekly ground water table with respect to BWDB benchmark,

(BWDB, 2000-2005).

2.4 FOUNDATION SYSTEM FOR THE STUDY AREA

In this section, the foundation systems which may be employed in the study area are,.-

-\. presented. These are:

(i) Buoyancy raft foundation

(ii) Piled-raft foundation

(iii) Deep pile foundation

~\,(:

20

2.4.1 Theoretical Background of Buoyancy Raft Foundation

The buoyancy raft works on a similar principle to that of a floating structure where the

>( supporting pressure for the raft is obtained by displacing the weight of earth or

overburden by the volume of a large voided foundation. Buoyancy raft is achieved by

making voids as a basement structure, Figure 2.5. It is designed s? th~t sufficient

overburden is removed to allow the superstructure load to be applied to the ground with

little or no increase in the original stress, which existed on the sub-strata. prior to

excavation and construction.

v

Superstructure

Basement introduced to reduce the effectiveground pressure due to the building weight

soft alluvial deposits

v

Figure 2.5 Buoyancy raft foundation (after Curtin et al., 1994)

Since buoyancy foundation are expensive compared to the traditional forms, they are used

where suitable bearing strata is at a greater depth. For this reason, this foundation system

tends to be restricted to site on very deep alluvial deposits where loads on the foundations

can be kept concentric.

The bottom of slab may be the basement of the proposed building and combined with the

ground slab and retaining walls. The raft design considers eccentricity of loads and aims

to keep differential settlements and tilting within the acceptable limits.

21

Inward yielding of sidesof excavation

Where the soil is predominantly cohesive, the reduction in ground stress will result in

heave Le. settlement in reverse. As with settlement, heave will have short-term (elastic)

~ component and long-tenn (consolidation) component. The short-term heave normally''"''.

occurs during the excavation period. Where its magnitude is considered significant, the

fonnation is then trimmed down to its required level. The long-term heave is dealt with in

the same way as long-tenn settlement. The anticipated amount of differential heave is

calculated, and the structure is designed to accommodate this movement. The heave of

the foundation is shown in Figure 2.6.

Settlement of 'groUIidsurface

I ,, d . . ,I Heave unng excavation I

L_~l-----------_J(al -- Design excavation level

Low-rise building

Heave of ground surface

Original groundlevel

- l--~bl-Uplift pressure on base slabbalances structural loading

Deep basement

Long-term heave ofbasement floor

Initial level of basement floor

Figure 2.6 Movements around a deep basement supporting a low-rise structure (a) On

completion of excavation (b) Final movements of completed structure (after Tomlinson, .

2001).

. rd... Q DThe net average app Ie pressure on SOl ISq =A - YJf

where the depth of embedment = Df

The factor of safety against bearing capacity failure for partially compensated foundations

may be given as

FS = qu(ne/) = qu(ner) (after Das, 1990)q Q -yD

A f

22

2.4.2 Case Study of Buoyancy Raft Foundation at Goalkhali Area2.4.2.1 Geotechnical Data

The upper 1.52 m depth layer is very soft clay. The layer between 1.52 and 3.05 m is soft

clay with decomposed wood. The underlying layer between 3.05 and 12.19 m depth is

silty clay. The layer between 12.19 and 18.29 m is clay with trace clay. A typical soil

profile of Goalkhali area is shown in Figure 2.7. The SPT-N value varies from 2 to 5 up

to the depth of 18.29. The unconfined compressive strength, qu varies from 11.53 to 66.33

kPa. The apparent ground water table is 300 mm below the EGL. The initial void ration

and compression index at the depth of3.05 to 4.5 m below the EGL remained in the range

of 0.89 to 1.0 and 0.32 to 0.48, respectively.

SOIL CLASSIFICATION

SubBUlfacedevation (EOL)

Verr Soft ClayGray Colour

Soft Clay with deoomposedwood and vegetalion

Silty clay

Clay with trace silt

"1oz-.~h:-cnal10 203040

N=4

LEGIM>:

~ 80flClay

• OrpticMItler

o SUtyFile sand

~ FincSllnd

E ClayeySik

~ SiltyClIy .

8iI ChrywithOrgmic:M!I1cr

~ Silt

Figure 2.7 Typical sub-soil properties in at Goalkhali, Khulna (after PWD, 2000).

23

Buoyancy raft foundation system for a five-storey hospital building was analyzed and

designed by the Design Division-3, Public Works Department (PWD). The foundation

system is shown in Figure 2.8. The foundation base was placed below the organic layer.

As the subsoil strata below the organic layer is very soft clay with high void ratio and

high ground water table, there was possibility of heaving of soil after excavation. To

minimize heaving, compacted sand with crushed aggregate was used below the mat. The

detail analysis and calculation of heaving at the bottom of excavation was not available.

No settlement plates were inserted to measure the settlement at periodical intervals.

P.L~ F.G.L

-< /( /02"CLER~ '"CLEAR

).~.;-E.G.L '_"cwe.<:

p ~/,'; ,';16mm"05-c.t

~~U 23"

n 7-8'~~i~gC!:-

~ ,....7'"

!""-OfEXCAVATI(t,I I ,'-'.16'.]"

N ,[1/ ....•.. 'DENSIREDAGGRlGATE+SAND

DECK BEAM

'"CLEAR

..... ~

Figure 2.8 Buoyancy raft foundation system at Goalkhali for five-storey hospital building

(after PWD, 2000).

2.4.2.3 Performance

Another, buoyancy raft foundation was analysed and designed by Shahedullah and

Associates Limited, Dhaka at Gollahmari (Khulna University area) for 4 storey.

Academic Building-II. Razzaque and Alamgir (1999) reported that the recorded

settlement was as negligible as 20 mm only.

24

2.4.3 Theoretical Background of Piled Raft Foundation

A piled raft foundation comprises both piles and a pile cap that itself transmit load

,a" directly to the ground. The aim of such a foundation is to reduce the number of piles

compared with a more conventional piled foundation. The piled raft is two types:

(a) Piled raft for settlement reduction

(b) Piled raft for load transfer

(a) Piled raft for settlement reduction: When the raft is safe from bearing

capacity considerations but it suffers from excessive settlement, a few number

of piles under the raft is used to relieve the raft of a part of the total load. As the

piles don not have to take all the loads, the number of piles require will be much

smaller than the traditional piled foundation. Because of some relief of the load,

the raft settlement will also fall within allowable limits (Varghese, 2005).

(b) Piled raft for load transfer: Piles are mainly designed to take up the foundation

loads and the raft only carries a small proportion (poulos, 200 1).

Simplified analysis method

Poulos-Davis-Randolph (PDR) Method

The ultimate capacity of the piled raft foundation can be taken as the lesser of the two

values:

(i) The sum of the ultimate capacities of the raft plus all the piles

(ii) The ultimate capacity of a block containing the piles and the raft, plus that of

the portion of the raft outside the periphery of the piles (Impe, 2001).

_.(An approach to combining the separate stiffness of the raft and the pile group has been

suggested by Randolph (1983). This approach is based on the use of average interaction

factor, Ocp, between the pile and pile cap. The pile cap stifIeness, kc and the pile group

stiffeness, kp, the overall foundation stifIeness,

kp +kc(l-2acp)kj=----- a;pkc1---kp

25

while the proportion of load carried by the pile cap (Pc) and the pile group (Pp) is given

by

The stiffness, kp,of the pile group (load divided by settlement) may be expressed as a

fraction 11•• of the sum of the individual pile stiffness, k. Thus for a group of n piles, kp=

11111nk while the group efficiency can be expressed as 11 •• =n-e. The exponent e lies between

0.40 and 0.60 for most pile groups.

The actual ewill depend on:

Pile slenderness ratio, e Id,

Pile stiffness ratio, A= Ep/GI

Pile spacing ratio, sid,

Homogeneity of soil characterized by p

and Poisson's ratio, v.

0.6

0.59

0.58Gl

i 0.57c 0.568.~ 0.55(j

0.54cGl'0IE 0.53.- w

---(, 0.52

0.51

/....•

.••..•......IV ~

/ ....•~

7 ...••...~

0.5o 20 40 60

Slenderness ratio LId80 100

Figure 2.9 Chart for calculation of efficiency exponent, e (after Fleming et al., 1992

26

0.8

0.75

0.85

10.80.60.40.20.7

o

1.1

1.15

1.05

~J!!c:1.0

.95

u 0.9CCII

!

.:;(.

Poisson's ratio, nu, and homogeneity factor, rho

Figure 2.10 Exponent correction factors (after Fleming et,al., 1992)

p.The stiffness of the single pile, k =_t

wt

417 21Tp tanh(;.d) R.---- + -------d h . f'ffi Pt (l-u)~ , ;.d fo

an t e equation 0 stl ness, - = 4 h( "0) R.w, 1+ 17_ tan ~,

7Z'A(l - v)~ (;.d) I!0

Where, 17 = rb , ratio ofunderream for underreamed piles'0

~ = Gf, ratio of end-bearing for end beari~g piles

Gb

p = G1I2, variation of soil modulus with depth for floating pile

Gf

E.A = _P ,Pile-soil stiffness ratioGl,= In(rmlro), measure of radius of influence of pile

;if = ( ; ) oso ( :, ), measure of pile compressibility

27

Where,

The average stiffuess of the pile cap may be estimated (Poulos and Davis, 1974) as

k = 2G -JBxLc I(1-v)

Shear modulus, Q = 200, for London clay (Simpson et aI., 1979).Cu

I = Influence factor (Poulos and Devis, 1974)B = Breadth of the raft

L= Length of the raft

Optimization, analysis and design of piled- raft foundation can be done through PLAXIS-

3D or GARP6 computer programmes. Behaviour of piled raft foundation depends on the

number, length, diametre, disposition of piles, raft thickness and geo-:technicaI properties

of the site (Cunha et aI., 2001).

y 2.4.4 Case Study of Piled Raft Foundation at Klang, Malaysia


The alluvial deposits at the site consisted of very soft to firm silty clay up to a depth of 25

m to 30 m with presence of intermediate sandy layers. The silty clay stratum was

underlain by silty sand. Klang Clay could be divided into two distinct layers at depth of

15 m. Some of the compressibility parameters of Klang clay are presented in Figure 2.11.


Both temporary surcharging and preloading technique was adopted to control long-term

settlement of the subsoil. Then the building was placed on top of it. The net fill height at

the site was about 0.5 m to 1.0 m The temporary surcharging heights remained in the

-1.. range of 2 m to 5 m. After the subsoil had achieved the required percentage of settlement",

and verified using Asaoka's method (Asaoka, 1978), the temporary earth fills were

removed and the construction of the foundation begins.

28

n,

:lS

- . ao • ... ..iC - . aD - ... .. -.. • .a III • •.. a.

'" ... •, ;: ••• ... • .- ..: la ••• •• J"•.

,.: ... . :~. +II • ...d~ •~•.. ) :t .""

.,-

:i.O . -. .a. • .,l:'~ ., :: '1lf .. ~ ...::~ .i. ..•.• " ; - - ••.-.. , "'I. • • ...

at. . I .""

0~ .....~ •• ••• •~.. ~ .

- ".. 0t" : ..... 0 .'" . • • .. . a :. " .Il . . •.. III ... ...e .... •• m. - .'"- "'=> _ . .. 0 . a ••• ... ...•.,S;tJ .•.. "" . II OIl •• ,.,aU

- ... ;... . A D • •~~

I I I , . I I

10

o

•• Z 3 •• 11020.:.ItO.«tm.l4567R' e.5 • I.~ o.'!i 0.1 0.1$ UI .zo .3'.0 Pi (lPn) OCR CR--C.n~ RR=C,n~ C.lm2J)Tl

Figure 2.11 Compressibility parameters of Klang Clay (after Tan et al., 2004)

The loadings of 5-storey apartments were highest at the columns and ranges from 100 kN

to 750' kN. The line load from the brick wall was 9 kN/m (4.5" brick wall) and the

uniform live load acting on the ground floor raft was 2.7 kN/m2 (1.5 kN/m2 live load +1.2kN/m2 floor finishing) as per recommended values given by British Standard 6399 (1996).

The main design criterion was to limit the relative rotation (angular distortion) to 1/350

(Skempton and MacDonald, 1956) to prevent cracking in walls and partitions.

The objective of the design was to provide an optimum piled raft foundation system that

takes into consideration the bearing capacity contribution of the raft and the piles

introduced mainly to limit differential settlement. The approach was to increase the

stiffness of areas where the settlement is expected to be the largest by introducing

settlement-reducing piles. Horikoshi and Randolph (1998) suggested that for uniformly

loaded raft, piles distributed over the central 16-25% of the raft area is sufficient to

produce an optimum design and for piled raft subjected to non-uniform vertical loads, the

use of piles with varying length would give the most optimum design (Reul and

Randolph, 2004). The foundation system adopted for low cost apartments consists of

200mm x 200mm reinforced concrete square piles with pile length varying from 18m to

24m interconnected with 350mm x 700mm strips and 300mm thick raft. Figure 2.12

shows typical section of the strip-raft foundation system and Figure 2.13 shows schematic.

view of the foundation system superimposed onto the completed low cost apartments.

29

100mm THK. S~llD .••nHPIJSl1C HEr U!liNG

200~2lJDmm Re. DRflorN PILEPEM E1RATIotl LENGTH ; "ARES

1

Figure 2.12 Typical section of the strip-raft foundation system (after Tan et al., 2004).

( -.r~_--=__ -_---=-_----_'-~'-l . _.--4~ _

~- ; - II; ~~~~-.-- •• ;;..;----' ...~--.£~-.,.--'f"J~ ... ...--.-..• II... .. II 11.8 ••• 1M •",1It.'" ."... • In I~'I'"n _ ••••• .11.... I. all In ••. ,fll.C ••• IiI ••• n_ ••••• III ••• n - I-.:. :~:.:,~_._.. :.. '! ~.~~.~:.:'~:~~.~:-r.:'.-.'...~ .;~_:.';..:~~,:':..'.~~. ~.~..~...~;.~.;....:.:

Figure 2.13 Schematic view of the foundation system (after Tan et aI., 2004).

The locations of the strips were adjusted during detailed design to ensure they pass

beneath all the columns (i.e. concentrated loads) for optimum structural design. Two

cases were considered in the detailed analysis of the foundation system, i.e.:

(a) Case I: Overall settlement behaviour

(b) Case 2: Pile-soil-structure interaction

Case I considered the overall settlement behaviour of the piled raft foundation system in

order to predict the settlement profile of the structural design. The settlement analysis was

carried out based on Terzaghi's I-D consolidation theory. Approximate adjustments were

30

made to the pressure imposed on the subsoil due to distribution of the super structure load

by the piles using concept of equivalent raft. The settlement profiles were then used to

determine the spring stiffness or Winkler's modulus to generate the overall stress on the

foundation raft due to the settlement profile.

Case 2 considered the interaction between the pile-soil-structure (foundation raft) of the

foundation system in order to determine the load distribution and local settlement of the

piles. The pile-soil-structure interaction can be carried out iteratively using elastic pile

interaction software (e.g. PIGLET/PIGEON) together with finite element structural

analysis software (e.g. SAFE) until convergence of results was achieved (typically

:t 10%). The iterative approach was proposed due to limitations of available software in

modelling pile-soil-structure interaction. The analysis could be carried out using 3-

dimensional finite element method (FEM) software (e.g. PLAXIS 3-D Foundation) that

could model 3-dimensional pile-soil-structure interaction. The solution for pile interaction

proposed by Randolph and Worth (1979) was; based on the solution for single pile and

extended for pile groups based on the principle of superposition. For cases with different

pile lengths, the interaction of pile bases at different levels was very complicated and its

effects to shear stress along the pile shaft were unknown. However, for the current

application in soft ground, the pile capacity was derived primarily from shaft/skin friction

with very little end bearing contribution.

2.4.4.3 PerformanceSettlement monitoring works was carried out when the building has been completed for

more than six months. The monitoring results showed that the maximum differential

settlement recorded was 27.02 mm. The relative maximum local angular distortion

recorded is 1/1215. The monitoring results also showed the building experiences marginal

tilt of approximately 1/1000. However the value was well within the limits of 1/250 to

1/500 (Charles and Skinner, 2004) for it to be noticeable.

31

.....j

2.4.5 Theoretical Background of Deep Pile Foundation

Pile foundation may be used to transmit the super structure load to the firm strata The

j, total capacity of a pile is due to both end and side resistance. Where the soil layer at

greater depth consists of dense layer, the cast in situ pile may be expected to have better

load resistance than driven piles.

Piles in Cohesive Soil

End-bearing pressure

The long term, drained, end -bearing capacity of a pile in clay will be considerably larger

than the undrained capacity. However, the settlements required to mobilize the drained

capacity would be far too large to be tolerated by most structures. For this reason, the

base capacity of the piles in clay is determined in terms of the undrained shear strength of

the clay, Cll, and a bearing capacity factor, Nc (Fleming et aI., 1992). Thus the end bearing

'r pressure is

The appropriate value of Nc is 9 (Skempton, 1951), although due allowance should be

made where the pile tip penetrates a stiff layer by only a small amount. A linear

interpolation should be made between a value of Nc = 6 for the case of the pile tip just

reaching the bearing stratum, up to Nc = 9 where the pile tip penetrates th(; bearing

stratum by 3 diameters or more.

Skin Friction

Driven piles

Point resistance of a pile embedded in soft clay is insignificant, it is seldom exceeds 10%

of the total capacity (Terzaghi et aI., 1996). The skin friction around a pile shaft has been

estimated in terms of the undrained shear strength of the soil, by means of an empirical

factor, ex , (Tomlinson, 1957) giving

The value of a appears to reduce from unity or more for piles in clay for low strength,

down to 0.5 or below for clay of strength above about 100 kN/m2. Cernica (2005) found

that the skin friction for driven piles was

32

T = 1.5cu tan ~

where, Cu = average cohesion, undrained condition

~ = angle of internal friction of the clay

The angle of internal friction of the normally consolidated clays can be computed in the

long-tenn shear strength case. Some commonly used long tenn S case shear strengths of

alluvial soils are as shown in Table 2.12

Table 2.12 Long term S case shear strength of alluvial soil (afte~ D~sign of Pile

Foundations, 1994)

Soil type USCS Consistency Angle of internal .

Symbol friction

Fat clay CH Very soft 13° to 1l'

Fat clay CH Soft 17° to 20°

Fat clay CH Medium 20° to 21°

Fat clay CH Stiff 21° to 23°

Silt ML - 25° to 28°

Fleming et at. (1992) showed the values of skin friction of driven piles in Figure 2.14.

-(

200

150

T.(kN/m2) 100

50

o

0

".. 0,.

0'0 I

a=1.3} 0

/: . .--o. ---/ . -0 .

-&"=0.33J ~ -.-,1 o 0 0 >-.-

.(. 0o 0 0

,1~:.J~ •• e!--

---50 100 150 200 250 300 350

c (kN/m2)

Figure 2.14 Relationship between skin friction and shear strength (after Fleming et aI.,

1992)

33

Bored piles

Weltman and Healy (1978) have analyzed a number of pile tests in boulder clays and

other glacial tills and suggest values of a varying with the undrained shear strength of thesoil as show in Figure 2.15.

220200180120 140undrained cohesion, C

100

drillen•••.•.• bore /JIles .

_ C1 il ('ncllid

- - Os ~caSf-i" __ ,-.---- ~~t ---- -----.:-------reduced values for driven pileswhere 1<1Od and fill is overlain by soh clay

80

1.2

1.0l:l

2 0.80

~ 0.6c0'(jj 0.4CD.c

"l\l 0.2

060

Figure 2.15 Variation of a with shear strength of glacial till (after Weltman lUldHealy,1978).

Cernica (2005) shown that the skin friction for bored piles was

t'=cutan~

where, Co = average cohesion, undrained condition~ = angle of internal friction of the clay, according to Table 2.12

Piles in Silt

End bearing

The pile tip bearing capacity increases linearly to a critical depth (Dc) and remains

constant below that depth. The critical depths are given as follows.

Dc= lOB for loose silts

Dc= 15 B for medium silts

Dc= 20 B for dense silts

The unit end bearing capacity may be computed as follows:

q = o'vNq

o-'v= -y' D for D < Dc0\= -y' D for D ~ Dc

34

Where, Nq = Terzaghi bearing capacity factor, Figure 2.16

a'v =Vertical earth pressure at the tip with limits

-:L At = area of the pile tip

000

•••

•••00

0: e.e~ 40

::u<~ .."iii:~ 10..z~

•

SUGGESTEDRANGE

o MIEYEAHOFa TERZAGHt & PECKo VEIUC DftlVeN• TO ••.•• NSON

IS t, 11 20 21 "0 •• 40 .1 60

• • ANGLE OF INTERNAL FRlCnON

Figure 2.16 Bearing capacity factor (after Design of Pile Foundations, 1994)

Skin frictionThe skin friction on a pile in silt is a two-component resistance to pile movement

contributed by the angle of internal friction (<\» and the cohesion (c) acting along the pile

shaft. That portion of the resistance contributed by the angle of internal friction (<\» is

limited to a critical depth of (Dc), below which the frictional portion remains constant.

The shaft resistance of piles in silt may be computed as follows:

fs= ky'D tan8 + a. c

where, D ~Dc

Qs= Asfs

Qs=capacity due to skin resistance

fs = average unit skin frictionAs = surface area of pile shaft in contact with soil

k = can be determined from Table 2.13

35

o =: depth below ground up to limit depth Dc

a =: adhesion factor, Figure 2.17

8 =: limit value for shaft friction angle from Table 2.14

Table 2.13 Common values for lateral earth pressure coefficient, k (after Design of

Pile Foundations, 1994)

Soil typeDisplacement piles Replacement piles

Compression Tension Compression Tension

Sand 2.0 0.67 1.50 0.50

Silt 1.25 0.50 1.0 0.35

Clay 1.25 0.90 1.0 0.70

Table 2.14 Values of shaft friction angle, & (after Design of Pile Foundations, 1994)

Pile material & .Steel 0.67 to 0.83 

Concrete 0.90 to 1.0 

Timber 0.80 to 1.0 

lCot-~ 1.0u.zoiiiw.J:~0,5II

0.25 0.1 0.75 1.0 2.0

o UNDRAINED SHEAR STRENGTH TSF

Figure 2.17 Values of a versus undrained shear strength (after Design of PileFoundations, 1994)

36

II•...

2.4.6 Case Study of Deep Pile Foundation


-~_ The upper layer between 4.5 and 6.0 m depth is soft organic clay. The layer between 6.0

and 13.75 m depth is silty clay. The layer between 13.75 and 21.50m depth is fine sand.

The SPT.N value of organic clay, silty clay and fine sand layers was found in the range of

2 to 3, 4 to 6 and 22 to 48, respectively. Typical borelog is shown in.Figure 2.18. The

unconfined compressive strength of organic clay and silty clay was found in the range of

18 to 90 kPa and 12.0 to 29 kPa, respectively. Cohesion, c and angle of internal friction,

 of fine sand layer vary from 5.75 to 7.5 kPa and 29.10 to 32.60°, respectively.

SOIL CLASSIFICATION

Subsurfilce

Organic ClayOeep Black Ooor, Bod odour

Vcry Soft ClayDeep Gmy Colour

Silty ClayLight Gmy Coloor

-_-_- .,.14

_-_-_ 16.16

Silty Fine Sand

----- 19.81

21.0]-_-_-

LEGEND:

~Soft Clay

• Organic Matlcr

83 fine sand

~ Clayey Sill

El Siltyaay

~ Clay with Organ;" Maller

...0 Silt with Organic Matter

'F Ground W_ Level

SAMPLE:o Disturbed Sample

••,01 Un-<liSIDrbed Samplc

N=50,over

",0

Figure 2.18 Typical borelog at Sonadanga area (PWD, 2006)

37


Four-storey residential building was analyzed and designed by Pubilc Works Department

.~ (PWD). The foundation system was precast reinforced concrete pile, the effective length: ! .

of pile was 45'-0" and the dimension of this pile was 12" x 12", Figure 2.19. The

allowable bearing capacity of was 50 kip and the pile is end bearing.

~

N~

f 12" fx-x section

~

y-y sectiony

xII II

" 7

'v

x

aI

in"lOt

y

I" Thick M.S. plate

Pile shoe

Long section of precast pile

Figure 2.19 Longitudinal section of precast concrete pile (after PWD, 20(6)

2.5 GROUND IMPROVEMENT TECHNIQUES FOR THE STUDY AREA

i In this section, the foundation systems which may be employed in the study area are

presented. These are:

(i) Rammed aggregate pier (RAP)

(ii) Preloading without vertical drain

(iii) Preloading with vertical drain

. (iv) Cut and replacement method

(v) Mattress foundation

(vi) Foundation accommodating large settlement,

2.5.1 Theoretical Background of Rammed Aggregate Pier (RAP)

Rammed Aggregate Pier (RAP) is used to improve peat and organic layer. In this method,

very stiff short aggregate piers are installed in cavities. The cavity is filled with crushed

stone in a number of layers and densified every small layer with high-energy impact

rammer. During the densification process, stone chips is pushed laterally into the sidewull

of the cavities and the soil surrounded the piers are stressed laterally. These combined

actions causes an increase of the confining pressure of the matrix soils, thus providing

additional load carrying capacity of the RAP.

The pier are designed and constructed to underlie approximately 35% or more of the

footing area of the overlying footing. The load carrying capacity of the RAP depends on

the friction angle of the material used in the cavities and the amount of confining pressure

affording by the surrounding media Again, the friction angle will depend on the

interlocking properties and the relative density of the aggregate. The friction angle of

densified crushed stone was measured as high as 50 degrees or more from full-scale field

test (Fox and Cowell, 1998).

As the stone chips are pushed laterally into the sidewall of the cavities and the sidewall of

the cavities is stressed laterally, strain of the soft soil to some extent can be achieved

during the construction of the RAP. Because of this prestrain, lateral bulging deflection

can be minimized under the compression loading of the structure (Handy, 2000). Thus,

39

depending on density and strength of the unimproved soil, the ultimate vertical bearing

capacity of a RAP element may remain in the range of 100 kips to 300 kips. Typical

RAP is shown in Figure 2.20.

.••••• 1

WEAK SOilS

Weak Soils orUnconlrolled Fill

Medium stiff10 sliHsdlsor be1ter

p ENGI~JEEREDFlll POVER WE.l\K SOilS

GClf1Ip'lcladE~ineeJEd Fill

Walk. Soils rrUo::onlrolledFill. ..

Figure 2.20 Design of RAP foundation (Farrell et al., 2004)

Settlement of the RAP supported footing is estimated by assuming that stiff RAP

elements and soft soil settle uniformly. For equal displacement, stress concentrates on the

top of the RAP element in proportion to the stiffness ratio of RAP to the unimproved soil.

In practice, stiffness ratio of RAP to native soil ranges from 10 to 50. The long-term

settlement can be calculated by using two-zone method, the upper zone (the aggregate

pier-matrix soil Zone) and the underlying lower zone, Figure 2.21.

Figure 2.21 Upper zone and lower zone concept (Farrell et aI., 2004)

40

The settlement of the upper zone settlement is:

Where,

qR .•(RaR .•+ l-Ra)s = -~'-----:;'-

kgp

s = Settlement of the Upper-Zone

q ::;footing bearing pressure

Rs ::; Stiffuess ratio of Geopier element to surrounding soil.

Ra= Ratio of geopier area to footing area.kgp::; Geopier stiffness modulus.

The settlement component of the lower zone is computed by using conventional

geotechnical settlement analysis on the assumption that the vertical stress intensity within

the lower zone is the same as that of a bare footing without the stiffened upper zone. The

combination of the settlements of these two-zone presents the total long-term settlement.

The RAP foundation system may be appropriate for low to medium rise building structure

for the KCC area. In this foundation system, confining pressure along the pier is

strengthened by the ramming action and intrusion of aggregate into the surrounding soil.

Since the sidewall of the cavities is non-uniform, the bond between ,RA~ and the soil

matrix will be more effective. Additionally, below the footing area 35% or more area is

covered by RAP i.e. a great portion of the organic clay is replaced by the crushed stone

and the remaining portion of it is strengthen by RAP construction. Therefore, organic

layer or interbeded organic layer may not reduce the capacity of the RAP.

The advantage of this technique is that it is very economical. This method can b{:used in

the city urban area without using shorepile and causing other problems. It is very faster

method of construction.

The disadvantage is that casings are sometimes are required for caving soil conditions.

Normally consolidated soft clays that extend more than 30 feet below the ground surface

can not be improved due to equipment restrictions.

41

2.5.2 Case Study of Rammed Aggregate Pier (RAP) at Beaverton, USA


The top 1.5 m depth layer was uncontrolled fill. The layer between 1.5 and 2.5 m depth

was peat. The underlying layer between 2.5 and 4.5 m depth was silt with organic matter.

The following layer was firm to stiff silt. The soil profile of the site is shown in Figure

2.22. The Standard Penetration Test (SPT) resistances varied from 3 to 6 blows per foot.

iLOG OF BORING B.1

f

~••• M~TE'UAlOEOCRlFi1ON

frll.si'iwithgr.ailel

2 pea ••.•soft

sil~ firmto '5~

10

Figure 2.22 Soil profile at site Beaverton, Oregon, USA (after Fox, 2000)


The aggregate piers were made by drilling 760 mm (30 inch) diameter holes to the depth

of 5.0 m from EGL. A small volume of 50 mm down sized crushed stone chips without

fines was placed at the bottom of each drilled cavity. This aggregate was then densified

-i" with high-energy impact rammer to form the bottom bulb, Figure 2.23. An undulated-~."sided pier shaft was formed in 300 mm (12 inch) thick lift by using well-graded stone

chips. The stone chips were further densified by the ramming action. During the process

of densification, the stone chips are pushed laterally into the sidewalls of the cavities.

This action causes an increase in the lateral stress of the matrix soil. The aggregate pier

soil reinforcement method substantially increases the bearing capacity of the reinforced

matrix zone and significantly reduces foundation settlement.

42

t.

~

.' '1\L

1. DRill. A CAVin'

/. '~' .._" •..::;/ /111\\\'

3. MAKE ABOnOMBUl!B

2. PLACE CLEAN STONE ATBOnOM OF CAVITY

4. BUILD GEO?fER SHAFT WITH0.3 m THICK LAY,ERS OF

HIGHWAY IBASE AGGREGATE

Figure 2.23 Construction process of rammed aggregate pier (after Fox, 2000)

Column loads were moderately heavy for this four-storey office building and ranged from

50 to 400 tons. Modulus load tests confirmed capacities of 40 tons per pier for the

relatively long piers up to 7 m in length. The piers extended into medium stiff sandy silts

through the fills and soft highly organic silt and peat soils. Allowable composite footing

bearing pressure was confirmed at the relatively high value of336 kPa (3.36 tsf).

Soft ground at the campus of Khulna University of Engineering and Technology was

improved by using RAP. The ground at the site consists of soft fine-grained soil up to

great depth with a layer of organic soils at 4.5 to 9.0 m depth fro the EGL. The RAP was

cylindrical shape having 0.75 m diameter and 3.40 m length. It was installed manually as

single, double and group. Field measurement showed that the ultimate bearig capacity of

footing resting on single, double and group RAP treated ground increased by 1.5, 1.8 and

1.96 times, respectively (Hossain, 2007)

2.5.2.3 Performance

The building experienced excellent settlement performance with observed total

settlements of less than 20 mm (0.80 in). The modulus load test data indicated that the

pier did not bulge appreciably during increased load intensity. The pier provided

43

-4

significant side friction to resist essentially full load tip to a stress intensity of about 960

kPa (9.60 tst).

2.5.3 Theoretical Background of Pre loading without Vertical Drain

The simple preloading means that a surcharge equal to a future site load, is applied. When

consolidation ofthe foundation soil is practically complete (90 % of total settlement), the

surcharge is removed and the new building is erected. This ground improvement

technique is suitable for normally consolidated soft clay, silt and organic deposit. The

functions of preloading are to gain bearing strength and to reduce its compres.sibility

within the time available for the preloading operation.

The final settlement under the surcharge is,

_ Cc H I Po + PIs.t! --- .og---1+eo Po

where, S sf = final settlement due to surcharge

H= thickness of consolidating layer

eo = initial void ratio of representative element of soil

Cc = compression index

Po = initial vertical pressure

PI = stress increase due to surcharge

The rate of settlement (vertical condition),

The settlement s, at time t can be expressed as

s, = U.s f

where, U. is the average consolidation ratio (vertical consolidation)

L M.a 2 -Ai'T W'lth m - 0 1 2 3U = 1 - -----=-e' - , , , ••••.•••" ", ••0 M 2

where, M = (2m+1}rr/2

t = time, s

C = coefficient of vertical consolidation, m2/s•

44

lelev+ 2ml

• s: settlement plate• B. Standpipe piezometer with active port

. between "'elf -10 and -12m

• P: g~ gl~~~:::i:O/~ active port

L = longest drainage path in clay layer, equal to half of H with top and bottom

drainage and equal to H with top drainage only.

Terzaghi suggested the following equations for u ,

For u == 0 to 53 %: T =!!..-( u % )2, , 4 100

Foru, =53tol00%: T, =1.781 -0.933 [log (100 -U%)] (afterDas, 1985)

2.5.4 Case Study of Pre loading without Vertical Drain


The site was 150 kIn northwest of Athens, Greece, on a coastal plain of moderate seismic

activity. The building location was covered by marshland, the referenced to low sea level

was +0.30m. Previous indUstrial installation adjacent to this site had been founded on 12-

16 m piles. The area plan of the building was 144 m long, 33 m wide and 16 m high,

Figure 2.24. It was used to store ore, in heaps up to 14 m high, weighing 21.6 kN/m3, and

having an angle of repose of 40°.

__ ~Uine~~~~~~ __ ~ ~_1I I

Base of prelooding heap IIII

IIIII

I I--.:-t---------~-Ji 9 1fl 2fJ 3p ,,?m

Figure 2.24 Plan of site preparation (after Stamatopoulos and Kotzias, 1985).

Five boreholes showed recent random deposits of soft and compressible soils, as far down

as elevation -10.9 In, Figure. 2.25, with some increase in strength below -9.5 m.

45

0: ..

103..

c::::J GRAVEL FlU.~GRAVELlllIIJSANO

[l]]]]SII..T~CI..AY~ PLASTIC CI..AY

.~ ORGANIC CLAY~PEAT

.21?"

0

E

z:0

-& ~C:>•••-'•••

-10

-1

Figure 2.25 Boringlogs at coastal plain (after Stamatopoulos and Kotzias, 1985).

STANDARD PENETRATION RESISTANCE (bIOWS/O.3M>

00 10 20 30 40 50

0»!.' I

0 IT befje PretOQflngf0

000. • • A OUpperboundary after ~)'

-20 0 I~ 0 ••• .1 0 Before pretoadinge 0 • • After preloading~0 • ...z-4

0 000 •- ., ,

I- 00 A. .-<-6 .. •o - .. v -,

>0 ..- • •1&I

00 000

..;I •-8 •1&I

08 0_ 0

~.-.-10 e

0i ••

0 B L,r boundary ..•••• I .

.

Figure 2.26 Standard penetration resistance versus elevation (after Stamatopoulosand Kotzias, 1985).

Starting at -10.9 m, there was layer of very stiff clay (CL) of different provenance and

older geologic age. The soil types, the results of standard penetration test was shown in

Figure 2.26

46


The decision was taken to preload the site by creating 12 m height embankment of total

'r earthwork volume 65, 000m3• The preload was 1.8 times of the permanent structure. The

resulting settlements under the preload were expected to be 0.76 m along the centerlineand 0.48 m along the footings.

2.5.4.3 Performance

The improvements ofthe soil were as follows:

1. The water table showed a rise, from elevation +O.4m before preloading to +O.80m

after preloading. The upper boundary of soft soils moved from about elevation -

0.30 m to about elevation -1.2 m. The lower boundary did not show much

movement and remained at about elevation -10.90 m.

2. The N value increased from an average of 6 blows/O.3 m, before preloading to 16

blows/0.30 m after preloading, that is it increased by 168 %. The zero and other

very low values (16 results of 0,1 and 2 blows/0.30 m) that were observed before

preloading were completely eliminated, the lowest value observed after preloading

being 7 blows/0.30 m.

3. The increase is about the same for cohesive and cohesion less soils.

4. The in.situ permeability was decreased nine fold from mean value of 2.9 x 10.5

m/sec.

5. The mean value of the water content dropped from 31.5 to 26.90 %, which

corresponds to a change of the dry density approximately fr!Jm ,1460 to 1560

kg/m3• This result implies a reduction in volume by about 7 %.

6. The shear strength of clay determined from triaxial UU test increased three fold. In

case ofeU tests the mean value changed from 54 to 85 kN/m2 •

!.f.47

2.5.5 Theoretical Background of Pre loading with Vertical Drains

In a case where the rate of primary consolidation is too slow, the natural drainage layers

are supplemented by the installation of vertical drains. The vertical drain consists of sand

drains or prefabricated wick drains. The pattern of vertical drain and vacuum technique

are shown in Figure 2.27 and.Figure 2.28, respectively.

.,I

Figure 2.27 Pattern of equidistant drains (after Stamatopoulos and Kotzias, 1985).

48

.C

Suction pipe 1mperm eable sheet

InnniPV C drain m ateri 1

\Spacing PVD is 1.0 m Silty clay layer

. Sand layer

Figure 2.28 Vacuum technique used at Hazawa station, Japanese national railway(after Lee et aI., 1993).

The basic equation of radial consolidation

Due =cR(a2ue +1... aueJat ar2 r ar

mkwhere, C R =-!-J.L

rwCR = the coefficient of consolidation for radial drainage

kH= the coefficient of permeability in horizontal direction

i'. The solution for equal vertical strains is given by•....

U=I_e-2TR/F(n)

where, U is the average consolidation ratio

CRTR =-Jr2e

n2 3n2 -1 rF(n)=--ln(n)--- andn=-e

n2 -1 4n2 rw

"\

49 c

2.5.6 Case Study of Preloading with Vertical Drains

The effectiveness of sand piles in improving a typical soft ground at south western region

Bangladesh to construct a water control structure (6-vent regulator) in a river was

examined. At the site, a soft alluvium fine grained soil deposit exists up to 12m depth

from the ground surface. The site was improved by total 765 numbers of sand piles,

0.20m in diameter and 8.80 to 9.40 m long, installed in square grid at 0.75 m spacing by

vibro-displacement method. Typical sand of Bangladesh, Sylhet sand, is used in the sand

pile. Prior to the commencement of concreting for floor construction of regulator, sob-soil

explorations were performed to examine the improvement. The investigation reveals that

the sand piles improved substantially the bearing capacity of the natural ground.

Therefore, the soft ground improvement using sand pile technique is revealed as fast,

economical and an efficient method to improve weak soil compare with other.' ..

conventional ground improvement technique. The use of smaller diameter with close

spacing was found suitable in such soft soil deposits for the vibro-displacement type of

sand pile construction while comparing the construction problem arises for the

installation of large diameter due to the development of side friction (Hossain, 2007).

50

2.5.7 Cut and Replacement Method for Foundation in Khulna University Building. _2.5.7.1 Geotechnical Data

--t The subsoil formation of the Khulna University area shows the top 1.8 m thick layer

consists of very soft clay. The underlain layer between 1.8 m and 5.20 m from EGL is

soft clay with decomposed wood and vegetation. The layer between 5.20 m and 22.0 m

from EGL is soft clay with silt and organic matter and the following layer between 22.0

m and 35.05 m from EGL is the combination offine sand with silt and clay, Figure 2.29.

The unconfined compressive strength, natural moisture content, liquid limit and SPT-N

value of the upper 14 m thick soft clay layer varied from 20 to 28 kN/m2, 41 to 134 %, 50

to 75 % and 0 to 4, respectively. The percent of organic matter for the layer between 3 to

4.0 m depths from EGL varied from 42.79 to 49.81 %.


The mat foundation for the four-storey Khulna University Building was constructed over

compacted sand fill after removal of 4 m soft ground. The filling sand was a mixture of

two different sands of fineness modulus 2.2 and 1.2 at a ratio 1:1 and compacted properly

by sheep foot roller. During compaction, the optimum water content and the lift of sand

layer were 14 tol5% and 230 mm, respectively. The RCC mat of 305 mm to 457 mm

thickness was cast over this mixed compacted sand-filling layer. Detail of the foundation

system is shown in Figure 2.30.

2.5.7.3 Perfonnance

Razzaque and Alamgir (1999) studied the long-term settlement of this building during the

time period between February 1994 and March 1999, Table 2.15. The variation of

settlement (mm) with time (days) is shown in Figure 2.31. The Table 2.15 and Figure

2.41 show that the building settled by 508 mm during one and a half year construction

period. After this construction period, the building further settled by 252 mm within the

next four and a half year and wmost no settlement appeared after this time period. The

pattern of relative settlement was uniform and maximum angular of distortion remained

1/1299, which was far below the allowable limits. The above findings demonstrate that

cut and replacement method may successfully reduce differential settlement of jow-rise

51

"

buildings, which was built over soft clay. Here, the sand filling layers acted as stiffeningmedium to distribute the building loads uniformly.

t

Or", ..,ft d~.,.;dJ IlIilt

¥ •• lit orpni ••••

U!OI!NI>

~ Soft a.,.

• 0" •• MIlia

D BDtyrdMSa

~ YmcSIDd

mJ a...."Sili

~ lliltI'a.,

~ a.,.wlthOrwlai. MlIIta

<Jrcy tilt, ne, 1_ •••• m Sili

Figure 2.29 Typical borelog at Khulna University campus

(after Razzaque and Alamgir, 1999).

52

~I-D Ll

GROUND FLOOR

RL. +9.5'P.L.

RL. +1.5'

R.L.+l.5'

RL. -12.5'

F.G.L. Local Sand Filling

Mat 12"10 18.

Figure 2.30 Mat foundation on engineered fill for academic building-I at Khulna

University area (after Razzaque and Alamgir, 1999).

Settlement vs Time31 ~ ..•

2~~

1\ 1 Construction

\ period settlement,558.80mm.

\

\2 After constructionsettlement, 203.20

\ mm.

~3 No increase insettlement.

"~

..•.. --

0

-100

-200-E -300~ E- -400-c:Q)

E -500Q)

E -600Q)en-100

-800

-900o 250 500 750 1000 1250 1500 1750 2000 2250 2500

Time (days)

1/'I

'II (OU..'...'-ft:',

Figure 2.31 Observed settlements with respect to time of Academic Building-I at Khulna

University (after Razzaque and Alamgir, 1999).•...

I 53

Table 2.15 Records of foundation settlement for Academic Building-I (after Razzaqueand Alamgir, 1999).

Date Elapsed time, Settlement, Date Elapsed time, Settlement,days mm days mm

01-Nov-1992 0 0 Continuation of records27-Apr-1994 515 -557.78 29-Sep-1994 672 -635.51

05-May-1994 524 -566.93 12-0ct-1994 685 -637.03

12-May-1994 531 -576.07 03-Nov-1994 706 -644.65.

16-May-1994 535 -580.64 04-Dec-1994 737 -647.70

25-May-1994 544 -586.74 03-Jan-1995 767 -649.22

02-Jun-1994 552 -592.84 07-Feb-1995 802 -653.80

09-Jun-1994 559 -595.88 09-Mar-1995 832 -664.46

16-Jun-1994 566 -603.50 03-Apr -1995 857 -669.04

23-Jun-1994 573 -608.08 09-May-1995 893 -675.13

29-Jun-1994 580 -611.12 11-Jun-1995 926 -687.32

08-Jul-1994 589 -612.65 22-Jun-1995 967 -690.37

15-Jul-1994 596 -615.70 31-Jul-1995 1006 -691.90

21-Jul-1994 602 -618.74 31-Aug-1995 1037 -691.90

28-~ul-1994 609 -620.27 02-Nov-1995 1100 -696.47

04-Aug-1994 616 -624.84 11-Apr-1996 1260 -711.71-------~~- ~~---'---- t----"11-Aug-1994 623 -627.89 11-May-1996 1290 -7"19.33

18-Aug-1994 630 -629.41 26-May-1997 1670 -737.62~... - ..- ..._._-,-- ---~_..- ._-------_ ...."----_ .. ""--'" .__ ..~-._."--_._._--_.- ---. _._-_ ..._-.---_ ..__ ._._---_.~---_._-- ---._------_.-_ ..._-,._- --_ . -_.-._---_ .._---.24-Aug-1994 636 -629.41 01-May-1998 2010 -752.86

01-Sep-1994 644 -630.94 04-Nov-1998 2195 -765.05---_.,----- _. --_._--_ .._--- ._._-~~---- "-------- -------~-08-Sep-1994 651 -633.98 11-Feb-1999 2305 -765.05

15-Sep-1994 658 -635.51 28-Feb-1999 2322 -765.05

25-Sep-1994 668 :.s35.51 16-Mar-1999 2338 -765.05

54

..-I

2.5.8 Mattress Foundation for Boy's Hostel Building in Khulna Medical College

Area.


A generalized soil profile of the project site is presented in Figure 2.32. The DPL

(Dynamic Probing Light) tests were conducted to ascertain the depth of soft top layer

more precisely.

Plate Modulus MoistureSPT DPL (MPa) Condition Su (kPa) CJ(l+eo)

-10 0 10 200 10 20 0 2 4 25 50 25 50 0.1 0.20 •• •• •4

•• Organi••

...•

8 .JI' ----

\E Soft clay'-'..c: .••.- ..0- n •Q)

PL NMC LLCl 12 4

•.-

\••••16 lit... •

20 ..

Figure 2.32 Typical borelog at Khulna Medical College (after Kabir et aI., 1997)


,( Granular mattress used in column and wall footing were designed and constructed for

KMC building, Figure 2.33 and Figure 2.34. The function of granular mattress can be

described as the following. (a) Increase in bearing capacity by allowing very fast

dissipation of pore pressure, especially from the region immediately underneath the

geotextile layer. (b) Distribution of stress over a large area. (c) Minimize total and

differential settlement.

55

..,

Filling Sand

PL

. . .q

4Densified Sam Fill Type A or Type B

SandTypeB5300

q-

" -.<l •

ooM

(All dmensions are in mm)

Geotexlile ~~ed at bdlom of excavatill1

Figure 2.33 Detail of column footing on mattress (after Kabir et aI., 1997).

FGL

Filling Sand

4 ..

PL

Filling Sand'~.

...•

Densified Sand Fill

Dxnsi~~d AgJ~le .••.sand .F.ill.~ ..

(All dimensions are in mm)

Geolexlile placed al bottom of excavalion

Figure 2.34 Details of wall footing on mattress (after Kabir et aI., 1997).

The aggregate layer consisted of 2 parts crushed brick aggregates and 1 part course sand.

The crushed brick aggregate consisted of 25 rom down graded aggregate conforming to

56

--'--

the ASTM grading for concrete aggregates. The coarse sand consisted of river sand called

Sylhet sand, having fineness modulus ~ 2.5.

The fill layer consisted local sand having Fineness Modulus (FM) greater than 1.0. Fines

passing number 200 sieve was limited to 5 % for FM up to 1.5 and 10% for FM greater

than 1.5. The sand and aggregate were densified in layers by using twin steel drum

vibratory rollers. The densities of the materials were monitored by TRL dynamicpenetrometer.

A geotextile separator and filter layer was placed at the bottom of the excavation of the

soft clay layer. A nonwoven needle punched geotextile was used. The weight, grab tensile

strength and permeability were greater than or equal to 200 gsm, 750 Newton and 1 x 10-3

mis, respectively.

'1(' The rnodulii values for the aggregate layers were established from TRL penetrometer

tests and its indirect correlation with modulii. The modulii values for the clay layers were

calculated from the undrained shear strength, consolidation and screw plate load tests.

For the clays both undrained and drained modulii were calculated. Typical values for

sands, aggregates and clay layers are presented in Table 2.16. The modulus of subgrade

reaction for wall and column footing are presented in Table 2.17.

Table 2.16 Elastic modulii for the aggregates and clay layers (after Kabir et aI., 1997)

Aggregate/clay Modulii (MPa)

Sand 50.-

Coarse aggregate 80

Undrained 3.0Clay Drained 1.0

57

Table 2.17 Modulus of subgrade reaction for wall and column footings (after Kabir et aI.,1997)

Modulus of subgrade reaction Value in kN/m3

Ku 4240

I«I 1920

Kum 13180

I«Im 8970

Ku 1310

I«I 600

Kum 2170

I«Im 1250

2.5.8.3 Predicted Performance

Continuous inverted Tee beam type footings were used for load bearing walls and

continuous tapered footings were used for column found~tions of framed structures. A

beam on elastic foundation program based on finite element analysis developed by Hulse

and Mosley (1986) was used to analyze both the types of footings. Settlement and

distortion under working load dictated the proportioning and design of the footings. The

deflection of the footings for the foundation cases for wall and column footings are

presented in Figures 2.35 and Figure 2.36, respectively.

Wall load = 128.3 kN/m

. . . .i-.A ... ... ...

..••..-- -- ~ -

1106 1033106210341008982 960936617(kN)

I I I I I j I j II Io 5 10 15 20 25o

102030405060708090

100110

Undramed (With mattress)

nr~inf':ti (with m:4ttTf':';:~)

... . ... ... ... ... ..•..Undrained (without mattress)

I ~ - ...Drained (without mattress)

I111II111111111111111111111111111111111111111111111111111I

o 10 20 30mo

50

60

10

o 20o.~~ 30t+::~ 40Cl

Figure 2.35 Comparison of deflections of Figure 2.36 Comparison of deflections ofwall footing (after Kabir et aI., 1997) column footing (after Kabir et aI., 1997).

58

Four cases of foundations were considered to provide a comparative representation of

cases with and without mattress foundation as well as those under undrained and drained

~. conditions. The results in Figure 2.35 were for an inverted Tee beam wall footing, 1.45 m

wide, 33.2m long having 250 mm wide web and 300 mm thick flange. The findings

showed that provision of the mattress reduced the settlement to less than 1/3. Figure 2.36

showed the results of a typical strip footing for carrying column loads. The footing was

5.3 m wide, 410 mm deep and 27.3 m long. The concluding findings were that provision

of mattress foundation reduced the total and differential settlement into half than the

foundation system without mattress.

2.5.9 Shallow Foundation Accommodating Large Settlement.

Navy engineers of U.S.A designed a shallow foundation system that allowed 3 ft of

settlement. The design minimizes the risk of foundation failure without a pile system,

while saving about $ 355,000 of a project cost $ 2.20 million. The project was three......,'\ separated one-story buildings with ceiling heights of 23 ft. Maximum wall load was 5

kips per .linear ft and the maximum bearing wall span is about 140 ft. The building

finished grade was at about 6 ft above the original ground surface.


The sub soils consisted of 4 ft of recent medium dense silty fine sand, 55 to 60 ft of soft

silty clay with slight organic content and then dense silty sand extending to 120 ft deep,

Figure 2.37. The results of soil testing showed that silty clay material to have been

normally consolidated and to have high compressibility characteristics.


Settlement analysis indicated that the ultimate settlement resulting from the fill load alone

was approximately equal to 33 % of the height of the fill placed. To use sand drains along

with preloading by surcharge to accelerate settlement would require longer period for a

substantial settlement to take place. To use pile foundations to avoid large settlement of

the building would have cost 400, 000 US dollar for pile alone. Furthermore, support of

these buildings on piles, while allowing the surrounding ground to subside would create

untoward operation and maintenance problems.

59

o

~.

A foundation system consisting of strictly controlled engineered fill placed on a finn

stone base and inverted " T " shaped footings were considered for the suppm1 of the

buildings. Compacted structural fill which would act as a relatively,rigid mat could be

placed over the thick clay soil to support the proposed buildings. To promote uniform

settlement of the structural fill, a 2-ft thick layer of crushed stone, ranging from 2 to 6

inch in size was placed on the existing ground to increase the overall rigidity of the fill.

Settelment plate

Protection Box

+1

o

-1

zo

~...Jw.

Dense sand

Figure 2.37 Compacted was placed on a 2-ft thick layer of crushed stone

(after Wu and Scheessele, 1982).

The footings were designed as inverted "T" shaped grade beams. These inverted "T"

shaped footings were sized and reinforced to provide the strength required to t..arry the

superstructure, Figure 2.38.

60

The structural system for the super structure is load bearing masonry walls (composite

brick and concrete masonry unit) and open web joists for the partial second floor and the

,..l--- roof. The masonry walls are not flexible in terms of accommodating differential

settlements. The wall footings were designed to be rigid enough to bridge over or

otherwise resist differential settlements in the event that the footing lose support for a

span of 20 ft or a cantilever span of 10ft such as at a building corner. Considering these

potential footing subgrade problems, the inverted "T" beam footing sizes and reinforcing

were selected so as to provide the strength and effective moments of inertia required to

resist footing deflections.

b[" "4

" 4

. I v._2' ••"103'-8'

Concretemasonarywal

Potential subgrade subcidence wall footing

Potential subgradesubcidence - wall soling

5 ~ C7 D-~~~~2-0'~~~-~ cled

~ -_-_-_-_-_-_-_-_-_~I fill

Figure 2.38 "T" shaped grade beams footings (after Wu & Scheessele, 1982)"

61

(

2.5.9.3 Performance

The construction of this project began in August 1976. The average rate of settlement

measured after completion of the buildings was about 3 in. per year. About 16 % higher

than predicted by analytical results. From the beginning of the project to March 1981, the

average and maximum settlements were about 1.3 and 1.58 ft, respectively. No wall

cracks or structural distress of the buildings has occurred.

62

(

CHAPTER 3

GEOTECHNICAL INVESTIGATION PROGRAMME

3.1 GENERAL

The geotechnical investigation programme for the present study consists of both field testing

and laboratory testing. Field investigation was carried out at six selected locations. During

field investigation disturbed and undisturbed samples were collected. Laboratory tests were

performed at the geotechnical laboratory of Civil Engineering Department of Bangladesh

University of Engineering and Technology (BUET).

3.2 FIELD INVESTIGATIONS

3.2.1 Standard Penetration TestcJ In order to identify the subsoil stratification and collect disturbed and undisturbed soil

Q samples from different depths and locations, field investigation was performed in the form of~ .o Standard Penetration Test (SPT) in the study area at six selected locations, Figure 3.1. The-

locations are earmarked by Global Positioning System (GPS). These locations have heen

selected on the basis of previous available data and on the consideration of importance of the

existing structures within the area. For the purpose of identifying homogeneity of the subs~)il

formation, two boreholes were drilled at close interval at each selected location, i.e. in dl

twelve boreholes were drilled. Wash borings were carried out up to a depth of30.50 m from

the existing ground level at these locations. Reduced Levels (RL) of all the borehole

locations were determined with respect to the benchmark of Survey of Bangladesh (SoB).

SPT~Nvalues were recorded at every 1.5 m depth interval. Disturbed samples were collected

during recording of SPT-N values i.e. at every 1.5 m interval. Undisturbed samples were

collected from wherever practically possible. A list of undisturbed samples collected from

different depth in different borehole locations is presented in Table 3.1. Apparent ground

water level was recorded after 24 hours of wash boring at each borehole location

63/- ...•••...

~

.,-_.- .'C;<.~"'~' 'r" ,", '~.~Jlr3'- , 1iiI1GiijI_1lm<j -, .r'- 11(,.d.----;/ ..• -.--l.! .,y. .~! .•.• . , ,,--r-, ~..i""~: g e.tTrd./"m~ ----

)' L ~~-_J~_ - '" .ri=-')',T"~: ,~=:.lf#"'7-'!rf~l"",:I--" I .\i.'. '~~,.~' •..=u:;:..•.••""'" ~h"i .:-.::~~~'f..~(.,JI' J 1 .-;"1 - l\blI, .....,u~(•.•..ao.,., +"--. lata p,.... , la ~. JIIt_ ~/L-ndlRcmt .~__

. , ---:.. Phy~ical 71, -)J..4 .•..../ III L.. -l. \ ~ :. • " ~:~ ~~-"'" ~~::=o - 'HandIcraft ~ ' \' ,- , IN. ~ ""'" _._11?1-:.~.J'>;'t- lTraining Centre .~ • . ~ \\'\~ '--: I.I~ ~:;:::::;"''':.'':'(""",~.:=(f¥"Vi(1)~~ II;.' - ~\J' ~ '''''''''''''"""",,,,~IK<(').... -~-i;"Jtft~. .'( '1 "'~;lx)rll~t.:HA~.Jl"~j..., I ~::_\~'_- Khulna • r-;r ... ~,,_, -~-

'7 \ -1JI\ ., J •• j.... ' P Iyt h' " <e./l_~ """'" •r"d ' ~l " ~ • tl - 0 ec mc !i;.:;~,.;;;:;--•. ~ .- •, l' , I -, ••, ~ I • I t'jt t .' , _ ••...•••""/c... .•.P,.' 1 " , 11..-0'11 ; -(! ns u e '.',m, _ \ I I ~r'0-0: ~ \,ll:\"Co' , • , ,1 ;.?':'!"'~\'.'i!'" :--- ,./ '>~FJI 5~:"d 500 10,00 Meters~,;, h "V .\ t.i~: .~~. ., '..•(r;, .' "~~pj ~ /--- U::l '-.:.~ • ). "'. '~ .-- .,.. ~;:;r.a, £:j '. •

., '~.J It, hRa,.rMoool Q.; :-. -:. --i. /', I I , ~ •.•• -m.~bftqtam!'ipKe~" __ 5eBlll&

/'t I 1'.••• , ••• : • . *1 Lrl\ l (' ~~ ••I.:••=."f'M~~~==/. ._.!.at il1 .' "'- -=* •• of.KDA""p.I_~"'Sl'i'llSO

, • ••• ~ .••. , • , ~ •• n. '-'{'S ' ~ 1 •••••••••••- •• ------'''' .•• -••••• ~" •• • .•••. -. • c:::J "'. ~*CI.,.S'W'O~ ••• w.dIIStlIh.". 1/,-; \~ ... : t: I).' " • ~~ I 'L' .-- ..----...-...."'-..~

• \~, •• •• • l"JI!II J(. J",.... l.trlIJ~...,,......,(l)u.~• - g • , •• '~E+L:.all B' \ _-- ~"'-

" '~~~_ • fiiii _ ,. ",' ~ c> ~ ~ ~ ••..,..' . ~ \ .- •••• -I , I'/,jl, I' .Do :f'il, ,~. .""1 '" _ 1--__.

~\~ .~7!:6N~.....1

1-1' ~t:':'-A:#\d~ .... : :t\ ~Cl~~ ~--(;;tj/.~ j~I.':"'!iN\ • ,...•• ~. --~~\ '~ .i- .~~ I~-~~n:tjj;& ,.... ~. ~.- [::, , )~ ....rr I'J~,a........ )" .. -.. .' ., .• ~.' J • I '" 'J.j ',:IF RUI"SHA 11V."r-(~ • '..~

? , Kh I '.,~ "r. ~_. l ~-. ~_Y:' .~ ,II. , ~-".::::':-""'" .L1" una .••••••.,A rJ".'~ ~\ ~ , .. "",OV:.;" I '."~ ••••-...::.;::::,~<," Medical College. ~ ~ •• ' \J~\'I~ ~ '0,' .~, ••• .:.. ~,,' I c:1.~Q ~

. / Student Hostel , - ~ ..., ."'.': ~.n. ";;;.0 r«i~~' . ~ ~• •....• -i t •••... ~'. " .

J \ ' ,\ ~.[ .~~~ •• ~. ,. 0' •••• : '~~,A.~c~~~' .••••

~

~ I k... IV \-..==' ~_~_ :><:. '~ }: ~it 1!ld<~.". •-r:- A {\ 'f~,\ ~ ~ K. :J}'~ ' ;i;;'~ Sin~~ A '. l.: ". 7~~ i\Chmh-, I "/~ • \ - U-~~:.~ ~~ \ " '" -~< ;, ~ - l-\:f' '::'\. ~~ Ii I" -~" Thana ., _. ~ ' I. ~'Ij' 1 ~~,~~ ::Jl ~ ,",. . IT' JA~ r =. ~ ~' ...--=- --,.II 1\' .' •. i-. ' , "'_ '.,~ =.....,.",..=-< ,.... / \1 • rv.,- • .~ . . .v---::':::- •..I I • '-i r

~. :' .-,M>-, U '.J~r •.:.., I-J,-Cl~~ Holdlng#37, "'_'•. ~ __ :-_. ~~l~'rry.~ ,~r r--( rv- ~ .::;-'~t-..:li ',;' ~outh cen~ral Road_~ ~. ,~ :{--'jj "7"'D 1 ~:/J\, ~

• ~~l:b..(K/\~ ~.~"'=7\\ ~~~ ~~~~ •.• ' ..~ .:~'~':J1,1:lo..,.:" ,"'1ri1 ~r;... ..•.'..-., ,\ v.-. ~ • ~ 0" ~ ., -.;;, • -\'_ ~ 111 ~. \r , 1(-/ I ~ :=old!" r:r--z-e.",~ Rupsa FeryGhat -:." "j ~~~~ ,v ~ ...

~

'\)jJ ~ j .-:-1: ~f;::,~-J-\ ~,.~\:""~0/~~".:lIT," .. -_~ ~~~":b..~ ..•a "! ~:D1~"~j! .~"." !o.. • I I f I 1;. ~ ,--, •••.. - \ \· . I.,....'",,Lf \l'\H" if "c.1 "\lJ"~~Cci ',-~. \,":7:2' ryi - \~

.' . Ifk' I ~ ,,,.,r"(~l ,.M- r{~N . :l-~ .: : I •• \(Ilt.~~ \ "A ~ IWput ~.. .:::rL. ~ .'= ~. -L cz '" t=? ( ..:E::l:1::~;~~ '~::'DJ,-iilfiTI \ ~-..cw~, ~

.~. ,~ -.

~

~

Figure 3.1 Map ofKhulna City Corporation (KCC) area and borehole locations.

64

Table 3.1 List of undisturbed samples collected during SPT test.

BH RLof Depth of undisturbed samples (m) from IBorehole Locations

No. EGL (m) EGL

UD-I UD-2 UD-3

Holding no 37. South Central ----------- ----------

Road, Farazipara. 01 2.71 2.67 4.19 -(South Non-river side area) _._------ -------_ .. .--'--'---'-_._--'--"'--- - ._-----------_.

02 2.71 2.67 4.19 5.71

._--------- _ ..~.._-_.-

03 1.83 2.67 4.19 5.71NortJl-west Side of Atlas Food

Processing Office at Rupsa

Fe!)' Ghat, Rupsa. 04 1.83 2.67 4.19 7.24

(South river side)

05 2.04 2.67 4.19 5.49NortJl-west Side of Boys'

Hostel Building at Khulna

Medical College, Chota Boyra. 06 2.04 3.38 7.24 -(South Non-river side»

07 3.88 8.76 10.14 -South-west Side of Computer

Bhabon, Khuina Polytechnic.-- --- _.

Institute, Khalishpur. (NortJ\ 08 3.88 8.76 10.28 -side)

09 1.69 7.24 8.76 -South-east Side of HostelBuilding at Physical

Handicraft Training Centre, 10 1.61 7.24 8.76 -Goalkhali. (North side)

11 2.93 2.67 4.19 7.24South Side of OC Banglow,

Sonadanga Thana, Sonadanga.

(South Non-river side) 12 2.55 2.67 4.19 -

(_) Sign means samples could not be collected due to soft consistency

EGL=Existing Ground Level

65

3.3 GEOTECHNICAL LABORATORY INVESTIGA nONS

..}. The viewpoint of all the tests performed at the geotechnical laboratory of BUET is to

determine the index properties, shear strength properties and compressibility properties of the

collected disturbed and undisturbed samples. In order to identify the index properties, grain

size distribution, percentage of organic matter content (O.C) and specific gravity (Gs) were

determined using disturbed samples. Besides, natural water content (wo), degree of saturation

(S), liquid limit (wL), plastic limit (wp), and some additional grain size' distributions weredetermined using undisturbed samples.

Unconfined compressive strength tests and direct shear tests were performed on undisturbed

inorganic cohesive soil samples and disturbed sandy soil samples, respectively for the

determination of shear strength parameters, i.e. cohesion (c) and angle of internal friction (cP).

For the determination of the consolidation parameters such as compreSSiOnindex (Cc),

coefficient of secondary consolidation (ca), coefficient of consolidation (ev) etc., one-

dimensional consolidation tests were preformed on undisturbed inorganic and organic

cohesive soil samples.

Table 3.2 and Table 3.3 describe the sample depth, Borehole numbers and the name ofte~Ls

performed on disturbed and undisturbed samples, respectively. The relevant ASTM, BS and

AASHTO designations of the laboratory tests performed in the present study are shown. inTable 3.4.

66

i

Table 3.2 Summary of disturbed samples, depth and the name of laboratory test

Depth (m) from EGL BHNo. Name of laboratory test

2.67 1,2,3,4, 5, 11, 12 Specific Gravity, Sieve & HydrometerAnalysis

3.05 9 Specific Gravity, Sieve & HydrometerAnalysis

3.38 6 Specific Gravity, Sieve & HydrometerAnalysis

4.19 1,2,3,4, 5, 11, 12 Specific Gravity, Organic Content, Sieve &Hydrometer Analysis .

5.49 3, 5Specific Gravity, Organic. Content, Sieve &Hydrometer Analysis

6.10 1,2,9 Specific Gravity, Sieve & HydrometerAnalysis

6.103,4,5,6,7,8,9,10,11, Description and identification of soils by visual

12 manual procedure.

7.24 4, 6, 7, 9, 10, 11 Specific Gravity, Sieve & HydrometerAnalysis

8.76 7,8,9, 10, 11 Specific Gravity, Sieve & HydrometerAnalysis

10.29 8Specific Gravity, Sieve & HydrometerAnalysisSpecific Gravity, Sieve & Hydrometer

10.67 1, 2, 9, 11Analysis.

Specific Gravity, Sieve & Hydrometer16.76 3

Analysis

Specific Gravity, Sieve & Hydrometer19.81 1,2,4,6,9

Analysis.

Specific Gravity, Sieve & Hydrometer21.84 3,9, 11

Analysis.

Specific Gravity, Sieve & Hydrometer25.91 1,2

Analysis


Analysis

Description and identification of soils by27.43 1,2

visual-manual procedure


Analysis


Analysis

67

{

..~

Table 3.3 Summary of undisturbed samples, depth and the name oflaboratory test

Depth (m) fromBHNo. Name of laboratory test

EGL

Specific Gravity, Atterberg Limit,

Consolidation, Unconfined Compression2.67 1, 2, 3, 4, 5, 11, 12

and Combined Grain Size Analysis.


3.38 6Consolidation, Unconfined Compression



Consolidation, Unconfined Compression4.19 1,2,3,4,5, 11, 12


Specific . Gravity, Atterberg Limit,

5.49 5Consolidation, Unconfined Compression



7.24 4Consolidation, and Combined Grain Size

Analysis.


Consolidation, Unconfined Compression7.24 6,9,10,11



7,8: 9, 10, 11Consolidation, Unconfined Compression

8.76and Combined Grain Size Analysis.


10.29 8 Consolidation, Unconfined Compression


68

Table 3.4 Namtl,ofthe laboratory tests and the standards followed

SI. \ .Name of expenment Test Standard

No.

1. Standard Test Method for Particle-Size Analysis of Soil ASTM D 422-63

(Reapproved 1998)

2. Standard Practice for Description and Identification of ASTM D 2488-84

Soils (Visual-Manual Procedure)

3. Determination of Organic Content in Soils by Loss on AASHTO Designation:

Ignition T 267-86 (1993)

4. Standard Test Method for Specific Gravity of Soils ASTM D 854-98

(Inorganic Soils)

5. Determination of the Specific Gravity of Soil Particles BS 1377:1975

(Organic Matter)

-

6. Standard Test Method for Liquid Limit, Plastic Limit ASTM D - 4318-86

and Plasticity Index of Soils

7. Standard :Test Method for Unconfined Compressive ASTM D - 2166-86

Strength Test of Cohesive Soil

8. Standard Test Method for Direct Shear Test of Soils ASTM D- 3080-98

Under Consolidated Drained Conditions

9. Standard Test Method for One-Dimensional ASTM D- 4186-89

Consolidation Properties of Soils Using Controlled- (Reapproved 1988)

Strain Loading

69

CHAPTER 4

...•..•.•

TEST RESULTS AND DISCUSSIONS

4.1 GENERAL

Field and laboratory test data obtained from twelve boreholes are analyzed to develop soil

profile along the north south section of the study area. By employing Unified Soil

Classification System, USCS, it is found that the subsoil of the KCC l;lrea is very erratic and

layered in nature. The unconfined compressive strength tests of cohesive soil show low

compressive strength while the relationship between qu and SPT -N value presents wide

scatter. The deeper layer of the KCC area shows c-4>type of soil in which presence of silt

and mica gives them special characteristics to yield low angle of internal friction (4)). The

compression index, Cc of clay layer confirms the presence of normally consolidated soil

layer. The values of secondary compression index, Ca calls for considering as an important

parameter for foundation design within the study area.

4.2 IDENTIFICATION OF SUB-SOIL FORMAnON

On the basis of the geotechnical data obtained in this study, the KCC area may be divided

-f( into two parts namely north part and south part. South part may be further'divided into two

areas: non-riverside area and riverside area. Goalkhali and Khalispur area form the north

part. Chota Boyra, Sonadanga and Farazipara area comprise the non-riverside area and Rupsa

area represents the riverside area of the south part, respectively. Unified Soil Classification

System, USCS-ASTM D 2487-98 was used to identify and to classify the upper layer soils.

Visual-Manual Procedure-ASTM D 2488-84 and combined grain size analysis were used to

classify the layers below. Soil profiles with USCS symbols and SPT values along the North-

South section are presented in Figure 4. 1

70

.~.

North part South part•

'.

"

1

1

2

el 1

~t 44

6

12

16

2215

SI'24: i8

35

38

4233

~~ 2215

28

B.H.04EL 1.83

RupsaRupsa Fen Ghat'

River side area, Q

2

1

el 1('))1 1

4

64

21 13.1113 ~'

Sl18**. 23

11

30 20.7332

30

~' 26*. 3230

34

50 30.48'

B.H.03EL 1.83

21.03

10.06

30.48

I~4!27 *I I::t:5~18

4

2

1

~

1

::t: 28153 * 4

l S 3

I. * 10: 12q.T" . . 16

23

18~t 2021

36

33

40

50

50

'I

~III'

II

I)

50,0 !28.95

II1"

B. H. 01 I B. H. 02EL 2.71 'EL 2.71

25.0

14.93

~,t:

4.27 ::t: 25.18 * 1

2

3

~l~5

14

15

~ ~ 1215

20

24

2635

50#0 27.43

50,0

3

2

1

1

1, 2

" ~3

13

33

50,0

50,0

~~50, 0

:i

Sonadanga FarwparaSonadanga Police Station South Central' Road

14.63

50,0

50,027.43

~f3046

50,0

~*

B.H.11EL 2.93

14.63

27.43

B.H.06EL2.04

e. 1

~

~ 24.42 g 2

5.48 3

Sr 3*l 3

lo.0H 34

2e 5~ 4

9

6

6

523.01-1 6

3

S~ 5*

30.48U :

Non-river side area•Chotta Boyra ,Medical College

23.7

B.H.05EL 2.04

~

5* 3

10.3 12

9

6

@.1Ogt 14* 14

10

9

12

11

~

8S 6*~I 7

30.48 ,I 6

3

~I:1

if34

5

(')r 10::t:*~ 7

5

8

14

5

6

9

~l57

11

13

15

7.01

8.53

30.48

10

7

5

7

46~l412

8

: 6','',~

~.'tl

~

5

9

7

3

6~l68

4

el 7~ 4**

KhalishpurPolytechnic Institute

B. H. 07 B. H. 08EL 3.88 EL 3.88

6.71 I~8.23

19.81

30.48

~r81113

8

6

10

7

8

(')' 5=i.67

10

7

8

3

g~4•.••..

3.96

5.48

5

~r 6

=t 33

~23

10

S- 13:1 159

711

8

16

19~J232632

3639 30.48

USCSLEGND

GoalkhaliPhysical HandicraftTraining Centre

B.H.09EL 1.69

7.01

8.53

30.48

19.20

30.0

25.0

5.0

20.0

15.0

10.0

0.0

+5.0

Depth,m "SoB,B.M.

~

ML/CL, CLAYEY SILT

OH, ORGANIC CLAY

C~, LEAN CLAY

ML,SILT

CH,FATCLAY

MIl, ELASTIC SILTN

-+CUML, SJLTYCLAY -GWL

! .rv EXISTING GROUND LEVELSM, SILTY SAND '

I •• BASED ON A-CHART AND LIQUID AND PLASTIC LIMIT II OR GRAIN SIZE DISTRIBUTION ~

EL, ELEVf'\TIONWITH RESPECT • VISUAL MANUAL PROCEDURE 'TO SOB BENCHMARK il

B.M., BENCH MARK SoB, SURVEY OF BANGLADESH I' 28.95,30.48, LEFT SIDE NUMBER REPRESENTSTHE DIlPTH, ~. .' O,NVALVEOVER50 1,7, 18 RIGHT SIDE NUMBER DENOTES SPT-NVALUE(FIELD)

Figure 4.1 Soil Profiles and SPT~Nvalue along the North South Section in Khulna City Corporation Areal .71 .

~

t

35.0

,,'

~4.2.1 Identification of Subsoil in North Part

The top 6 to 7 m- depth from EGL in the north part is elastic silt (MH). The layer between

7 and 8.5 m depth from EGL is erratic organic clay (OH), which is fade black in colour

with trace of bad odour of decomposed wood. The layer between 8.5, and 19.0 m depth

from EGL is heterogeneous in nature. The soil of this layer varies from elastic silt (MH)

to clayey silt (CH/MH). Elastic silt (MH) is found at Goalkhali area while clayey silt

(CH/MH) is identified at Khalishpur area The layer from 19.0 to 30.50m depth from

EGL is again erratic in nature. The soil of this layer is fat clay (CH) with little organic

matter. Significant variation of this layer is found at Goalkhali area where, out of two

adjacent boreholes, one borehole shows fat clay (CH) and the other borehole contains silt

(ML).

4.2.2 Identification of Subsoil in South Part Non~Riverside Area

The upper 3 to 4 m depth from EGL in the south part non-riverside area is fat clay (CH)

in which 34 to 55 % particles are colloidal. The layer between 4.0 and 5.5 m depth from

EGL is an organic clay (OH) layer. The colour of this organic layer is deep black with

bad odour of decomposed wood. The layer between 5.5 and 13.0 m from 'EGL is very

heterogeneous in nature. The soil of this layer varies from elastic silt (MH) to clayey silt

(ML/CL). Elastic silt is found at Farazipara and Chotta Boyra area while clayey silt

app~s at Sonadanga area The layer between 13.0 and 30.5 m from EGL is again

heterogeneous in nature. The soil of this layer varies from silt (ML) to clayey silt

(ML/CL). Silt layer (ML) is found at Farazipara and Sonadanga area while clayey silt

(ML/CL) layer is identified at Chotta Boyra area.

4.2.3 Identification of Subsoil in South Part Riverside Area

The top 12.0 to 13.0 m depth from EGL in riverside area is clayey silt (ML/CL) in nature.

Unlike other areas, no organic layer is found below this top layer. The layer between 13.0

and 21.0 m depth from EGL is elastic silt (MH). The layer between 21.0 and 30.50 m

depth from EGL consists of silt (ML) with some mica

72

4.3 DETERMINATION OF REDUCED LEVELS

The reduced levels of salient locations of Khulna Master Plan (200 I) were found on the

basis of SoB benchmark. The reduced levels of borehole points were necessary to set up

the ground level with respect to common benchmark for developing the soil profile of the

study area. The reduced levels of salient locations, close to the borehole points, were

extracted from Khulna Master Plan (KMP). With the assistance of Khulna Polytechnic

Institute, a team consisting of author and a group of students of diploma engineering

surveyed twelve borehole locations to connect borehole points with the salient locations

of Khulna Master Plan. Figures 4.2 to 4.5 represent the different stages of the survey

work undertaken as part of this study.

" -~.. \.. .-- •... ~

Figure 4.2 Reduce level obtained from KMP

Figure 4.4 Placing of staff on base plate

73

Figure 4.3 Setting ofleveling machine

Figure 4.5 Taking of staff reading

4.4 GPS POSITIONS

~:\

The latitude and longitude of boreholes within the study area were determined by using

Global Positioning System (GPS) and these points were superimposed on the KCC area

map. All the latitude and longitudes of the borehole points are presented in Table 4.1 and

Figure 4.6.

Table 4.1 Latitude and longitude of boreholes points

Borehole Locations BO No. Latitude Longitude

Holding no 37, South Central 01

Road, Farazipara. (South non-river 22°48' 36" 89°34' 25"

side part)02

North-west Side of Atlas Food03

Processing Office at Rupsa Fery22°48'05" 89°34' 58",

Ghat, Rupsa. (South river side04

part)

North-west Side of Boys' Hostel05

Building at Khulna Medical22°49' 59" 89°32' 17"

College, Chota Boyra. (South non-06

river side part)

South-west Side of Computer 07

Bhabon, Khulna Polytechnic 22°50' 48" 'r.~ 89°32' 31"

Institute, Khalishpur. (North part)08-

South-east Side of Hostel Building 09 Clat Physical Handicraft Training 22°51' 27" 89°31' 53"

Centre, Goalkhali. (North part) 10 .sr,

South Side of OC Banglow, I I

Sonadanga Thana, Sonadanga. 22°49' 25" 89°39' 20"

(South non-river side part) 12

74

Figure 4.6 Khulna City Corporation (KCC) area map and borehole locations

75

4.5 LADORATORY TEST RESULTS AND DISCUSSIONS

4.5.1 Grain SizeDistribution

Combined sieve and hydrometer analysis was performed on 46 inorganic soil samples

(disturbed and undisturbed) as per ASTM D 422-63 (Reapproved in 1998) in order to

determine the grain size distribution of the collected soil samples at different depths and

locations. The distribution of percent sand, silt, clay and colloidal particles are presented

in Table 4.2. It may be noted that per cent fine sand, per cent silt, per cent clay and per

cent colloidal particles range from 1.0 to 70.0, 11.0 to 68.0, 6.0 to 45.0 and 12.0 to 72.0,

respectively in the inorganic subsoil layers of the study area ofKCC.

Table 4.2 Summary of grain size distribution of inorganic Soils

Depth (m) Grain size distributionLocation BH Soil type fromEGL Fine sand ("!o) Silt ("!o) Clay ("!o) Colloidal ("!o)

'\ 2.67 10 20 20 50.- CHVJ 6.10 6 22 21 510 1s::9- ,

MH 10.67 28 41 11 20:::s "Tj

g ~ ML 19.81 52 26 7 156.~-< .t1l"O 3.05 1 9 45 55"'1 ~~.~ CHQ. 6.09 2 33 31 34t1l

"0 2~ MH 10.67 1 64 12 23'-'

ML 13.72 70 35 13 22MUCL 2.67 2 60 10 28MUCL 4.19 6 68 9 19.- ;,

VJ 3 MH 16.76 32 48 12 180c::9- ML 21.84 25 44 9 20:::1. :-tl-< c:: ML 27.43 38 34 10 18~"t:len en..... ~Q. MUCL 2.67 2 46 16 36t1l"t:l~ MUCL 4.19 10 52 16 22'-' 4

MUCL 7.24 3 39 20 38MH 19.81 60 42 6 12

!I

76

Continuation of Table 4.2

Depth (m) Grain size distribution

LocationBH Soil type fromEGL Fine sand (%) Silt (%) Clay (%) Colloidal (%)

() 5 MUCL 4.19 1 30 24 45=:TaIII

(JIOJ MUCL 3.35 30 60 5 5-.00.,<ro iil-g-;::J.cn 6 ,MUCL 7.24 3 32 25 40~g-=:T....•

<' MUCH 19.81 40 30 10 20ro....•

z~ 7 CH/MH 7.24 3 42 20 35o gos-1r-"'.e~ ~ ~ CH/MH 8.76 1 34 27 38'-"

MH 3.05 50 35 7 8

Q MH8 6.10 10 40 20 30~t=: MLZ 9 19.81 4 64 16 160

S-~

ML 22.86 1 34 15 35'-" :

ML 30.48 18 32 6 20

en CH 2.67 1 11 16 720::lIII0. MUCLIII 7.24 2 48 20 30::l<0III-en ML0 11 10.67 2 48 18 32c-=:T::l0 ML::l 13.72 2 60 18 20I

:::::I.<ro....•(JI ML 21.33 3 59 18 200:ro~2: 12 CH 2.67 2 15 21 62

• Classification based on USCS, thc range of fine sand, sill, clay and colloidal is 0.425-0.074, 0.074-

0.005,0.005-0.001 mm, < (>.001mill, respectively.

77

[

+'.

, "

4.5.2 Organic Matter Content

Organic matter content was determined from disturbed organic soil samples at different

depth and different borehole locations. AASHTO (1993) method was used in the

laboratory to determine the organic matter content. Table 4.3 shows the summary of

organic matter content at different depth and different borehole locations. It may be

noted that percentage of organic matter content in the study area of KCC ranges from

13.0 % to 43.0 %. Presence of this significant amount of semi or fully decomposed

organic matter is likely to lead to remarkably high water content, high void ratio, high

compressibility and low shearing strength.

Table 4.3 Summary of organic matter content at different borehole locations.

BH DepthOrganic matter Usual range of organic

Location (m) from Soil typeNo. Content (%) content (%)

EGL

Farazipara Organic clay (a) 42.79 % at a depth ofBH-Ol 4.19 43.00

(South non- i(OH) 2.89-3.35 m depth and

river side Organic clay 49.81 % at a depth of 2.43.BH-02 4.19 37.0

Khulnapart) (OH) 2.89 m at

Chota Boyea University (Razzaque and

(South non- Organic layer Alamgir, 1999)BH-05 4.57 32.74

river side (OB).

part) (b) Percent of Organic

Organic layer Content remains in theBH-07 7.16 41.44 range of 5-30 % up to

Khalishpur (OH)

(North part) Organic layerdepth of 12 m in Bagerhet

BH-08 7.62 31.00 at Mollahat-Noapara Road(OH)

Section (Munshi, 2003)

BH-09 4.19Organic layer

20.00Goalkhali (OB)

of Organic(c) Percent(North part) Organic layer Content remains in theBH-lO 4.19 13.00

(OH) range of 0-30% at depth of

Sonadanga Organic layer43.82

up to 15.0 m (Islam, et aI.,BH-ll 4.57

(South part) (OH) 2003)

78

\\y

-+- 4.5.3 Specific Gravity

Specific gravity was determined from disturbed samples at different depth and different

borehole locations. ASTM D854-98 described method was used to determine specific

gravity for inorganic clay or silt. British Standard 6399 (1975) designated method was used

to determine the specific gravity of organic matter. Table 4.4 shows the summary of the

values of specific gravity of both inorganic and organic soil samples at different depth and

different borehole locations. It may be noted that specific gravity of the inorganic clay

samples ranges from 2.58 to 2.86. The usual range of specific gravity for inorganic clay

varies between 2.68 and 2.75 (Bowles, 1997). The reason oflower than usual value may be

attributed to the presence of some organic matter and the difference of upper range of value

may be due to the presence of significant amount of colloidal particles. The values of the

specific gravity for organic clay vary from 1.61 to 2.29. The usual values of specific gravity

for organic clay vary from 2.14 to 2.17 (BRTC, 2003) or may be even less than 2.0 (Bowles,

1978).

Table 4.4 Summary of the values of specific gravity of different types of soil samples

81. Total No.

NoSoil Type

Of SamplesGsRange Usual Range of Values

Inorganic clay,

1 (CL, CH and CWCL and 182.58 - 2.86 2.68-2.75 (Bowles, 1997)

CL-ML)

Variable but may be under 2.0

(Bowles, 1978) and as low as 2.30

to 2.40 are not uncOirunon

2. Organic clay (OH) 6 1.61 - 2.29 (Bowles, 1997). Moreover,

specific gravity, Os is as low as

2.14 in Khulna Medical College

(BRTC, 2003)- ------~~

3.Inorganic silt,

31 2.60 -2.82 2.62 - 2.68 (Bowles, 1997)(ML, MH, MUCL)

i

79

; r;

4.5.4 Natural Water Content and Degree of Saturation

iNatural water content (wn) and degree of saturation (S) were estimated from the data,

obtained from unconfined compression tests and consolidation tests performed on

undisturbed samples of different depth and different borehole locations. Attempt has been

made to compare the values for same type of soil at same depth for different boreholelocations.

At i67 m depth where the soil type is fat clay (CH) to elastic silt (MH), the natural moisture

content and degree of saturation vary from 30.70 % - 39.90 % and 93.0 % - 100.00 %,

re~pectively. At 4.19 m depth where the soil type is organic clay (OH) at Farazipara, the

natural moisture content and degree of saturation range from 157.0 % to 212.0 % and 100.00

%, respectively. Except Farazipara, at 4.19 m depth; the soil is clayey silt (ML/CL) at Rupha

-+ (Rupha Ferry Ghat Area), elastic silt (MH) at Chota Boyra (Khulna Medical College) and fat

clay (CH) at Sonadanga (Sonadanga Police Station). The water content and degree of

sa~rationofsuch wide range of soil types at these locations remain in the range of33.0 %-46.90 % and 81.40 -100 %, respectively.

Again, the soil type at 7.24 m depth is silt (ML) in nature; the natural moisture content and

degree of saturation range from 33.30 % to 43.00 % and 95.60 % to 98.60 %, respectively

e;'(ceptat Goalkhali area. At 8.76 m depth the soil type is elastic silt (MH) to fat clay (CH);

tht; natural moisture conte!lt and degree of saturation remain in the range of 38AO % to 50.30

%and 86.55 % to 99.60 %, respectively. A summary of the values of natural water content

"'"'(- an~ '.iegree of saturation is presented in Table 4.5. It may be noted that the ranges of the

values of natural moisture content and degree of saturation of the subsoil of the area given in

the ~'ablecompare well with the values reported by BRTC (2003) for Khulna Medical

College. The presence of such high moisture content and degree of saturation indicates that

the subsoil of the study area of KCC is likely to exhibit low shear strength and highcompressibility.

80

-.-:;/

-+

Table 4.5 Summary of natural moisture content and degree of saturation

Borehole Depth (m)S (%)

'Yb, 'Yd,

Location Soil type 00(%)No from EGL kN/m3 kN/m3

Holding no 37, SouthFat Clay, CH SH-OI 2.67 33.6 .93.00 17.97 13.45

Central Road, Organic clay, OH SH-OI 4.19 157.0 100.00 11.31 3.78

Farazipara. (South

non-river side part) Fat Clay, CH SH-02 2.67 3').') 100.00 17.87 12.78

Organic clay, 011 SII-02 4.1') 212.0 100.00 11.19 3.02

Clayey silt, MUCL SH-03 2.67 30.7 16.46 12.59North-west side of

Atlas Food SH-03 4.19 31.0 95.10 14.33 18.23

Processing Office at8H-04 2.67 32.3 19.42 14.86

Rupsa Fery Ghat,

Rupsa (South river Clayey silt, MUCL BH-04 4.19 33.0 81.40 16.97 14.26

side part)BH-04 7.24 33.3 17.51 12.99

DH-05 2.67 31.1 95.40 18.08 11.51

North-west and Side

of Boys' Hostel Clayey silt, MUCL DH-05 4.19 46.9 100.00 16.77 11.41

Building at KhulnaSH-05 5.49 52.1 95.20 14.32 7.95

Medical College,

Chota Boyra (South BH-06 3.38 32.0 98.60 17.76 14.31

river side part). Clayey silt, MUCLSH-06 7.24 43.0 96.75 17.13 11.97

South-west ~ide of Silty clay, CHlMH DH-07 8.76 40.7 98.00 17.20 12.20

Computer Bhabon,

Khulna Polytechnic BH-08 8.76 50.3 86.55 16.34 10.67

Institute, Khalishpur Silty clay, CHlMHBH-08 10.28 35.4 84.70 19.80 17.26

(North part).

South-east side of BH-O,) 7.24 41.8 95.60 17.00 11.67

Hostel Building at Elastic silt, MH

Physical HandicraftBH-O,) 8.76 43.7 99.60 16.65 11.82

Training Centre, BH-I0 7.24 40.8 98.60 17.73 12.58

Goalkhali (North E13l>1icsilt, Mil

part). 81-1-10 8.76 38.4 92.02 17.37 12.28

---BH-II 2.67 35.3 100.00 18.52 13.69

South side of DC Fat Clay, CH

Banglow, Sonadanga 81-1-1I 4.19 34.0 94.60 17.82 13.30

Thana, SonadangaClayey silt, MUCL BII-II 7.24 31.3 90.60 18.60 14.77

(South non-river side

part). 2.67 35.9 95.10 17.64 12.98

~ Fat Clay, ell 1311.)24.19 52.9 97.70 16.29 10.65

81

4.5.5 Atterberg Limits

..tASTM D-4318-86 described method of Atterberg Limits Test was performed on 24

undisturbed samples at different depths of different borehole locations to determine liquid

limit, plastic limit, and plasticity index. A typical flow curve is presented in Figure 4.7 and a

summary of the natural moisture content (ron), liquid limit (WL), plastic limit (Wp) and liquidity

index (lL) is shown in Table 4.6. It may be noted that ooL and wp for inorganic soil samples

vary from 31 % to 79 % and from 16 % to 40 %, respectively. However, ooL and oop for

organic soil samplesyary from 109 % to 114 % and 55 % to 57 %, respectively.

A-chart has been prepared and liquid limit (ooL) and plastic limit (oop) data have been verified

by drawing V-line. Figure 4.8 is the graphical presentation of the A-chart. It may be noted

r that most of the 'data representing the soil lies along A-line except organic clay (OR). 12 out

.~. of 23 representing data lies below A-line, which indicates that these are either silt (ML) or

elastic silt (MH). The remaining 11 data lies above the A-line, which suggests that these are~

either lean clay (CL) or fat clay (CR).

By way of example, a typical graphical presentation of natural moisture content (000), liquid

limit (ooL), plastic limit (oop), and liquidity index (IL) with respect to depth at Farazipara

(South Central Road) is shown in Figure 4.9. Comparing 000 with ooL and Wp, it can be

concluded that the upper 3.0-4.0 m layer is normally consolidated soil. The values of

liquidity index (IL) ranging from 0.44 -0.75 suggest low shear strength of the soil layer. The

underlying 1.25-1.5 m normally consolidated organic clay layer with IL varying in the range

'~. of 1.13-2.73 indicates liquid-like behaviour (Bowles, 1997).

The following 9.0-10.0 m layer is also normally consolidated soil with low shear strength

having liquidity' index (lL) in the range of 0.45 - 0.96.

82

..~.

Table 4.6 Summary of Atterberg Limits

SoilLocation BH Dep. (m) Wn %) WL Wp Ip IL

type

CH BH-OI 2.67 33.6 61 28 33 0.17

Holding no 37, South OH BH-OI 4.19 157.0 109 55 54 1.89

Central Road, 59CH BH-02 2.67 39.9 25 34 0.44Farazipara (South non

...

river side part). 011 BH-02 4.19 212.0 114 57 57 2.73_.

CH BH-02 7.24 77.0 79 31 48 0.96

MUCL BH-03 2.67 30.7 31 22 9 0.97

North-west side of BH-03 5.71 31.0 32 16 16 0.94Atlas Food processing

office at Rupsa Fery BH-04 2.67 32.3 36 22 14 0.75

Ghat, Rupsa (SouthMUCL BH-04 4.19 33.0 32 22 10 1.13

river side part).

BII-04 7.24 33.3 41 23 18 0.59

MUCL BII-05 2.67 31.1 53 32 21 0.29West and North Side of ------ ._-_ ..---- ~--- - ..-- _.- __ ._-_- ---------_.- ._--_.---- ~._----Boy's lIostei Building MUCL III 1-05 4.19 46.9 41 27 14 1.47

at Khulna MedicalMil BH-05 5.49 52.1 67 40 27 0.45

College, Chota Boyra

(South non river side MUCL BII-06 3.38 32.0 37 27 10 0.49

part).Mil BH-06 7.24 43.0 48 32 16 0.69

South and west Side of MUCL BH-07 8.76 40.7 44 27 17 0.83

Computer I3habon, .....--.- -_--- '--------- .

MH BH-08 8.76 50.3 58 32 26 0.72Khulna Polytechnic

------ ----- -_...._ .._._-- ------- ------ ----Institute, Khalishpur CHlMh 1311-08 Hl.28 35.4 40 28 12 0.63

South and east side of MI1 BH-09 7.24 41.8 54 31 23 0.46

Hostel Building at

Physical Handicraft Mil 811-09 8.76 43.7 46 32 1.4 0.87

Training Centre.-

l\UI BI-l.1O 7.24 40.8 46 32 14 0.65Goalkhali. (North

part). MH BlI.IO 8.76 38.4 46 32 14 0.45

South side ofOC CH 811.11 2.67 35.3 51 20 31 0.49

Banglow, Sonadanga... --- ..------

CII BII.II 4.19 34.0 51 16 35 0.52lllana , Sonadanga ----

(South non river side MUCL BlI-11 7.24 31.3 38 18 20 0.66

part). ---'- ------ -~.---.._ ...._---- ._--- ----CII 2.67 35.9 63 18 45 0.40

----_. 81-1-12 _._._- ... _-.-_._---_. ----_- .._-"----- ---- _._'CII 4.19 52.9 53 19 34 1.00

83

FLOW CURVE4.

60.00

--- 57.50~~'-'.•.. 55.00=~.•..= 52.500Ul-

50.00~=~ 47.50

'"~ -...52.50 "lIIIl

\.

45.001 10

Number of Blows

25 100

Figure 4.7 Flow curve of sample at 2.67 m depth in Chota Boyra

(Khulna Medical College) area.

A-Chart

30

Plasticity (Clays) or Compressibility (Silts)

low Medium High

The equation of "A" lineHorizontal at 1p=4 toWL ~ 25.50 then ~.,Ip =O.73(WL-20)

"'"(11"

Inorganic clay of

*"The equation of 'U" line high plasticity ,,'Vertical atWl=16 to Ip =7, U-lin~•• ". ./ ""then Ip - O.90(WUI) " CH, H

Inorganic ~",,- / <>clay of , <>

4emedium

*" <> ./plasticity -'<>/

V MH, OHInorganic .",*" <>- c1ayoflow

*' LOl~

<> Inorganic sills of highplasticity ""," compressibility and- *'~ v

~<>v organic clays

". o~ Inorganic sills of medium I I

====="k~(= .=,=;~:"v ....- compressibility and

MLO organic sills

0 10 20 \30 40 50 60 70 80 90 100 110 120 1

100

90

80

70

60

~--It l 50,eo( . ••,

"] 40~~ 30..!lll.

20.

10

0

Inorganic silts of lowc~mpressib~lity

liquid limit, Wd%)

Figure 4.8 Position of the cohesive soil samples on Casagrande plasticity

chart.

84

plastic limit (oop) and liquidity index (Idwith,depth at South Central Road, Farazipara.

~.~ Figure 4.9 Graph showing the variation of natural moisture content (oon), liquid limit (ood,'. "\.

lHl44. • --.2.73 • • •

• 0.96 • •

• Liquid Limit

• Liquidity Index

100 125 150 175 200 225755025

A Natural Moisture Content

• Plastic Limit

2.67

8.01

o1.34

6.68

4.01

.s:::.Q. 5.34CDC

-E-

85

4.5.6 Shear Strength Characteristics

"-#-STM D2166-86 described method was used to determine unconfined compressive strength

of 14 undisturbed inorganic cohesive soil samples collected from 2.67 m to 10.29 m depth

from EGL. The values of different parameters obtained from these tests are summarized in

Table 4.7 a.ndF,igure4.10 is the graphical comparison of the qu values with respect to depth.

It is found that SPT-N values varying from 1 to 7 and qu values range from 7.0 to 119.0 kPa.

Typically, the values of qu range from 2 to 166 kPa at the depth between 3.5 and 9.5 m in the

southwest zone of Bangladesh (Serajuddin, 1998).

Attempt has been made to derive relationship between Nand quo From the graphical

presentation between Nand qu in Figure 4.11, it can be concluded that no definite relationship

can be drawn between SPT-N and qu values of the inorganic cohesive soil samples of the-(study area of the KCC.

It may be noted that no unconfined compressIve strength of organic samples could be

determined due to difficulties involved in preparing test specimens.

86

16.515.013.5

qu = 65.0 kNlm2

Ol = 39.9 %Gs=2.61'Yd=12.78 kNlm3

'Yb=17.87 kNlm3

5= 100.0 %e, =9.0%N=2

12.010.59.07.5

III

qu = 22.0 kNlm2

Ol =77.0 %Gs=2.62e=1.68

'Yd=11.51 kN/m3

'Yb=15.72 kNlm3

5=99.9%e, =9%N=1

6.04.53.01.5o0.0

80

70

60-•.•.€~ 50'-'

=C"

i 40e-rI1.~ 30'"'"eS' 20QU

10

Strain (%)

I ~UD-01. 2.67 m ~UD-03. 5.71 m I

Figure 4.10 Unconfined compreSSIvestrength of 2.67 m and 5.71 m depth at South

Central Road (Farazipara) area.

ck..r

87

.~-

Table 4.7 Summary of qu and SPT-N value of inorganic cohesive soils of different depth

and different borehole locations.

Depth NLocation BH Wn value qu (kPa)

Cu = qu/2 Ef 'Yd(m) (%) (Field) (kPa) (%) (kN/m3)

BH-OI 2.67 33.6 3 70.00 35.0 6 13.45

Farazipara._._._~---- 1---- 1---

(South non-river BH-Q2 2.67 39.9 2 65.00 32.5 9 12.78side part)

I

BH-02 5.71 77.0 I 22.00 11.0 9 11.51

Rupsa.(North part) BH-04 4.19 33.0 2 92.00 46.0 7.0 14.33

Chota Boyra. BH-Q5 5.49 52.1 I 30.00 15.0 10 7.95

(South non -riverside part) BH-Q6 7.24 43.0 3 93.00 46.50 11 11.97

BH-Q8 8.76 50.3 4 89.00 44.50 11.00 10.53Khalishpur.(North part)

BH-Q8 10.28 35.4 5 83.00 41.50 12.0 13.54

BH-Q9 7.24 41.8 2 41.00 20.50 15 11.51

Goalkhali.BH-IO 7.24 40.8 3 61.00 30.50 15 "12.58

(North part)

BH-IO 8.76 38.4 4 119.00 59.50 10.5 12.28

BH-II 4.19 34.0 2 41.00 20.50 9.0 13.3

Sonadanga.(South non-river BH-12 2.67 35.9 2 51.00 25.50 12.0 12.98

side part) -_.-- -_.

BH-12 4.19 52.9 1 7.00 3.50 15 10.65

88

'-' ..';,140

120

100

-: 80..lIl:

c- 60

40

20

.•..

0 [[ [J

[0r

[r

~

oo 0.5 1 1.5 2 2.5

SPT-N3 3.5 4 4.5 5 5.5

Figure 4.11 Graph showing the relationship between qu (kPa) and SPT-N value

ASTM D3080-98 described direct shear test method was used to determine shear strength

parameters, c and <t>of 8 disturbed samples collected from a depth of 19.81 to 28.95 m

from EGL. The shear strength parameters, so obtained, have been compared with the

usual range of values of such parameters suggested by Meyerhof (1974) and Peck et al.

(1974). Moreover, the comparisons and graphical presentation are shown in Table 4.8. It

may be recalled that deeper layer of KCC soil is c-<t>type in which silt is a dominating

part with the presence of mica. Moreover, the values of relative density deduced from

field N values and effective overburden pressure, p'o according to Gibbs and Holtz (1957)

equation. The obtained relative density reveals that the compactness of the soil ranges

from loose to dense. Moreover, the obtained angle of internal friction, <t>(deg.) is lower

than the values suggested by Meyerhof (1974) and Peck et al. (1974) with relation to the

relative density. The reason may be attributed to the presence of mica content and organic

matter with silt. However, a useful relationship may be drawn between <t>and N for the

range of soil samples collected from 19.81 to 28.95 m depth, Figure 4.12. The equation

between field SPT-N value and angle of internal friction, <t>(deg.) may be drawn as:

<t>(deg.) = 0.28 N (field) +22.72

89

Table 4.8 Summary of shear strength parameters

BH DepthN p'a

RelativeCompactness

Observed Usual range ofvalue density Shear strength friction angle, cj>

Peck, Hanson

(m) (Field) (ksf) Dr(%) c (kPa) <j>(deg.) Meyerhof and(1974) Ihombwn

(974)

1 21.33 20 3.29 59.50 Medium 7 31 35-38 30-36

1 25.9 35 4.04 73.13 Dense 14 34 38-41 36-41

3 21.94 32 3.17 76.29 Dense 21 32 38-41 36-41

3 27.43 30 3.93 68.38 Dense 11 32 38-41 36-41

4 19.81 28 3.15 71.47 Dense 29 26 38-41 36-41

6 19.81 10 2.95 43.68 Loose 28 25 30-35 29-30

6 26.52 8 3.99 35.11 Loose 52 24 30-35 29-30

7 28.95 8 4.14 34.64 Loose 38 26 30-35 29-30

40.35

-e-=- 30-:S;E 25-e=e 20.a.s 15•••=J ~

-~ ~ 10~

5

.. - ••I

• •.- = O.28N 22.72

o5 10 15 20 25

SPT-N value30 35 40

Figure 4.12 Graph showing the relationship between angle of internal friction, cj> and

SPT -N values

90

4.5.7 Compressibility Characteristics

~'"FoUowing ASTM D2435-96 one-dimensional consolidation test method was used tol

determine compressibility properties of 20 undisturbed inorganic and 2 undisturbed organic

soil samples collected from different depth at six borehole locations. The results obtained

from these tests are discussed below.

4.5.7.1 Compression Index

At 2.67 m below from EGL, the obsetved compression index, Cc of inorganic soil samples at

Farazipara, Rupsa, Chotta Boyra and Sonadanga area ranges from 0.17 to 0.40. This

compares well with the usual range of Cc that remains in the range of 0.20 to 0.50 for

. normally consolidated clay (Sing, 1992). The obtained compression index values have also.

been compared with the different equations of the same types of soil proposed by different

~,. researchers, Tahle 4.9. The theoretically calculated Cc values obtained from these equations

and obsetved Cc values obtained from the laboratory tests are shown in Table 4.10. It may

t..e noted that the Cc values obtained from Nakase (1998), Terzaghi and Peck (1967), Azzouz

(1976) and Al-Khafaji and Andersland (1992) equations are comparable wlth the obsetvedvalues.

Again, at 4.19 and 7.24 m depth, at Rupsa, Chotta Boyra and Sonadanga area and at 8.76 and

10.28 m depth at Goalkhali and Khalishpur area the obsetved Cc values have been also

compared with the calculated values obtained from the equations in Table 4.9. It may be

noted that the Cc values ofNakase (1998), Terzaghi and Peck (1967), Azzouz (1976) and AI-

_~ Khafaji and Andersland (1992) equations compare well with the observed values at different

depth for inorganic soil layers.

91

." !

Table 4.9 List of equations used to calculated Cc for inorganic cohesive soil samples (after

Bowles, 1997)

Compression Index, CcEquation

Comments Source/ ReferenceNo.

Cc=O.009(WL-10) Eq-l Clays of moderate St . Terzaghi and Peekand (:t 30% error) (1967)

Cc=1.15(eo- 0.35) Eq-2 All clays Nishida (1956)

Cc= 0.009 WN+ 0.005 WL Eq-3 All clays Koppula (1986)

Cc= 0.046+ 0.0104 Ip Eq-4 Best for Ip < 50 % Nakase et al. (1998)

Cc= 0.37 (eo+0.003L+O.OO04wn-0.34) Eq-5 678 data points Azzouz et al. (1976)

Cc = -0.156+ 0.411eo+ 0.00058 WL Eq-6 62 data points AI-Khafaji andAndersland (1992)

The compression index, Cc of organic soil samples collected from Farazipara location ranges

from 1.95 to 4.01. The compression index, Cc values of the organic clay layer is compared

with the calculated values obtained from NAVFAC (1982) equation originally suggested for

organic soils, Table 4.11. It may be noted that the observed values exceed the calculated

values considerably. Such high values of Cc suggest that the organic soil strata in the KCC(

-.)".., study area are highly compressible.

92

--r"

Table 4.10 Summary of actual and calculated Cc values of inorganic soils of different locations and

depth./.'

Location BHDepth Wn Ip

Observed Theoretical Cc

(m) (%)WL eo c,

Eq-1 Eq-2 Eq-3 Eq-4 Eq-5 . Eq-6

ll\)"rl BH.Ql 2.67 33.6 61 33 0.83 0.40 0.46 0.55 0.61 0.39 0.25 0.22~~~~lf BH-02 2.67 39.9 59 34 0.95 0.26 0.44 0.69 0.65 0.40 0.30 0.27

BH.Q3 2.67 30.7 31 9 0.97 0.17 0.19 0.71 0.43 0.14 0.27 0.26

,-., BH.Q3 5.71 31.3 32 16 0.62 0.20 0.20 0.31 0.44 0.21 0.14 0.12CIlo :::cc c BH.Q4 2.67 32.3 36 14 0.87 0.25 0.23 0.60 0.47 0.19 0.24 0.22=r"Ol~~ BH.Q4 4.19 33.0 32 10 0.61 0.16 0.21 0.30 0.46 0.15 0.14 0.11

BH.Q4 7.24 33.3 41 18 1.14 0.33 0.46 0.55 0.61 0.39 0.25 0.22

("") BH.Q5 2.67 31.1 53 21 0.84 0.27 0.38 0.56 0.55 0.26 0.25 0.22goiii BH-05 4.19 46.9 41 14 0.89 0.38 0.27 0.62 0.62 0.19 0.26 0.23tJj~p3 BH.Q5 5.49 52.1 67 27 1.53 0.35 0.51 1.36 0.80 0.32 0.52 0.51,-.,~~ BH.Q6 3.38 32.0 37 10 0.83 0.18 0.24 0.55 0.47 0.15 0.23 0.21

"0

~ 43.0 48 1.19 0.67 0.34 0.97 0.69 0.21 0.38 0.36~ BH-06 7.24 16,l

BH.Q7 8.76 40.7 44 17 1.19 0.34 0.30 0.97 Q.58 0.22 0.37 0.36~[ i"

So 1;;' BH.Q8 8.76 50.3 58 26 1.58 0.38 0.43 1.41 0.74 0.31 0.53 0.53l.g"~~ BH.Q8 10.28 35.4 40 12 0.78 0.54 0.27 0.49 0.52 0.16 0.21 0.19

~ZlBH.Q9 7.24 41.8 54 23 1.20 0.33 0.40 0.98 0.65 0.28 0.38 0.37

~o~s. BH-09 8.76 43.7 46 14 1.40 0.46 0.32 1.21 0.62 0.19 0.45 0.45"

BH-l1 2.67 35.3 51 31 1.00 0.36 0.37 0.75 0.57 0.36 0.31 0.28,-.,~~ >~••

~i BH-ll 4.19 34.0 51 35 1.14 0.43 0.36 0.91 0.56 0.40 0.36 0.34I100,;-,1\)

BH-ll 7.24 31.3 38 20 0.87 0.22 0.25 0.60 0.47 0.25 0.24 0.22

93

Table 4.11 Summary of borehole locations, soil type, observed and calculated Cc values of organic

soils at Farazipara.

Depth Wn Observed TheoreticalLocation Soil type BH Cc

(m) (%) eo Cc NAVFAC (1982)

Organic clay, BH-Ol 4.19 157.0 3.11 1.95 1.81OH

Farazipara.Organic clay, BH-02 5.71 212.0 6.15 4.01 2.45

OH

4.5.7.2 Secondary Compression Index

The values of secondary compression index of the inorganic soil samples obtained from the

y' consolidation tests vary from 0.0010 to 0.0075. Table 4.12 shows the equations used to

calculate secondary compression index (Bowles, 1997) for fat clay,CH to elastic silt, MH

while Table 4.13 shows the comparison between observed and calculated values of

secondary compression index, Ca. It may be concluded that NAVFAC (1982) and Nakase et

al equations describe KCC soil of the study area better than the Mesri et al. (1990) equation.

Table 4.12 List of equation of secondary compression index and references (after Bowles,.

1997)

Secondary compressionComments Source/ Reference Equation

index, Ca

Ca=O.OOOlwn - NAVFAC (1982) Eq-l

Ca=0.00168 + 0,.00033Ip - Nakaseet al. (1988) Eq-2

Ca =0.015 to 0.03Cc Sandy clay Mesri et al. (1990) Eq-3

94

. I

Table 4.13 Comparison between actual observed and calculated Cn ,

Depth Cc WnObserved Theoretical, Co:

Location BH Ip Co:,(m) (%) (l00 kPa) Eq-l Eq-2 Eq-3

BH.Ql 2.67 0.40 33.6 33 0.0010 0.0040 0.0125 0.0090

Farazipara.BH.Q2 2.67 0.26 39.9 34 0.0037 0.0036 0.0128 0.0059

BH.Q3 2.67 0.17 30.7 9 0.0015 0.0031 0.0046 0.0038

BH.Q3 5.71 0.20 31.0 16 0.0037 0.0031 0.0070 0.0045

Rupsa. BH.Q4 2.67 0.25 32.3 14 0.0014 0.0032 0.0062 0.0056.

BH.Q4 4.19 0.16 33.0 10 0.0020 0.0027 0.0050 0.0036I

BH.Q4 7.24 0.33 33.3 18 0.0020 0.0033 0.0074 0.0074

;

BH-()5 2.67 0.27 31.1 21 0.0015 0.0032 0.0083 0.0061.BH-05 4.19 0.38 46.9 14 0.0044 0.0047 0.0062 0.0086

ChoUa BH.Q5 5.49 0.35 52.1 27 0.0075 0.0052 0.0103 0.0079Boyra.

BH.Q6 3.38 0.18 32.0 10 0.0010 0.0032 0.0049 0.0041

BH.Q6 7.24 0.67 43.0 16 0.0050 0.0050 0.0070 0.0151

BH.Q7 8.76 0.34 40.7 17 0.0024 0.0041 0.0072 0.0077

Khalishpur. BH.Q8 8.76 0.38 50.3 26 0.0018 0.0050 0.0101 0.0086

BH.Q8 10.28 0.54 35.4 12 0.0019 0.0035 0.0054 0~0122

BH.Q9 7.24 0.33 41.8 23 0.0030 0.0042 0.0092 0.0074

Goalkhali. ,

BH.Q9 8.76 0.46 43.7 14 0.0025 0.0044 0.0063 0.0104

BH-ll 2.67 0.36 35.3 31 0.0023 0.0032 0.0117 0.0081

Sonadanga. BH-ll 4.19 0.43 34.0 35 0.0023 0.0034 0.0129 0.0097

BH-II 7.24 0.22 31.3 20 0.0018 0.0031 0.0082 0.0050

I,.(i,

95

(

4.5.7.3 Coefficient of Consolidation

-f Coefficient of consolidation, Cv of inorganic clay samples was determined by using both\

Casagrande arid Taylor's method. However, the Cv values for organic clay layer was

determined by using Taylor's method only. The Cv values for inorganic clay samples remains

in the range of 1.0 to 4.0 m2/yr and 3.12 to 8.98 m2/yr, obtained respectively on the basis 0'£

Taylor's method and Casagrande's method. However, the Cv values for organic clay remains

in the range of 22.70 m2/yr to 25.10 m2/yr, for an effective pressure 50-100 kPa, Table 4.14.

It was found that Casagrande's method was not suitable for organic clay or very soft clay

layer while Taylor's method matched well for every types of soil.

4.5.7.4 Coefficient of Volume Compressibility

The coefficient of volume compressibility, mv has been determined for an effective pressure

.~..r of 50-100 kPa. It was found that the mv values of inorganic soil samples remain in the range

of 0.3408 to 0.6240 m2/MN while the mv values of organic soil samples remain in the range

of 0.8210 to 1.220 m2/MN, Table 4.14. The observed mv values of both inorganic soil and

organic clay samples have been compared with the usual range of mv values for the

respective soil types. The observed mv values of inorganic soil samples remain in the usual

range of mv values of normally consolidated alluvial deposits reported by Sing (1992).

4.5.7.5 Coefficient of Permeability

The coefficient of permeability, k values have been determined on the basis of Cv and mv for

both inorganic and organic clay layers, Table 4.14. The observed values ofk for clay, organic

J-. clay and clayey silt or silty clay remain in the range of2.49.-11.22 x 10-9 mis, 5.89-8.59 x 10-

9 m/s and 1.02-7.13 x 10-9 mIs, respectively. The observed k values are compared with the

usual range of k values for respective soil types reported by Cernica (2005) and Peck et a1.

(1974). It may be noted that the upper layer ofKCC soil formation is practically impervious.

~v 96

-( Table 4.14 List of calculated mv and penneability at different depth at different borehole

locations

'f/,

DepthCasagrande' Taylor's Method

my, k (mls),Method m2/MN (x 10-9)

Location Soil ~ : BHCv, Cv, m2/Yrm2/yr (50-100

(m) tso(min) (50-100 t90(min) (50-100 kPa)Taylor's Method

.'kPa) kPa)

~i CH BH-Ol 2.67 2.95 5.27 4.00 16.82 0.6240 3.25

~.. OH BH-Ol 4.19 2.56 22.70 1.2200 8.59

:1_.go en CH BH-02 2.67 1.80 8.98 3.24 21.03 0.3408 2.22

~g-..-S- OH BH-02 4.19 2.25 25.10 0.7566 5.89

.g MUCL BH-03 2.67 2.50 5.73 6.76 9.17 0.3588 1.02

!!I.~ MUCL BH-03 5.71 2.56 19.05 0.4089 2.41go---'O~~ I::

MUCL BH-04 2.67 1.27 67.51 0.3408 7.13cET~.(1)

MUCL BH-04 7.24 2.13 31.48 0.5943 5.80..•

(') MUCL BH-05 2.67 5.50 2.82 2.56 26.19 0.3408 2.77is ::;r:::I06. g

MUCL BH-05 4.19 5.80 2.64 5.06 13.07 0.8210 3.330< tIlo 0..•«!!I.S

MUCL BH-06 3.38 1.00 64.69 0.2961 5.94~.(1) ••••••

~[ MH/CH BH-06 7.24 2.12 31.96 0.5724 5.67

'2:;0:: MUCL BH-07 7.24 1.50 10.22 3.06 21.39 0.5363 3.56o [So Vi'

~f CHIMH BH-08 10.28 1.27 52.96 0.4731 7.77-..- .

'20 MH BH-09 7.24 1.20 12.51 4.41 14.73 0.5646 2.58o 0H MH BH-09 8.76 2.10 30.93 0.4213 4.04-..-;:I. CH BH-ll 2.67 1.00 67.36 0.5372 11.22o<---C/)(1) C/) 0;;: g $

CH BH-Il 4.19 4.60 3.12 3.61 17.18 0.4680 2.49_. S- ~~ ~~o()Q9 1" MUCL BH-Il 7.24 1.80 8.62 1.25 53.55 0.4033 6.69-..-

97

CHAPTERS

SUGGESTED GROUND IMPROVEMENT TECHNIQUES

AND FOUNDATION SYSTEMS FOR THE KCC AREA

5.1 GENERAL

This chapter includes different options of ground improvement techniques and relevant

foundation systems for the KCC area. The ground improvement techniques are mat with

Khoa mattress,. Geopier or Rammed aggregate pier (RAP) and preloading with vertical

drains. Relevant foundation system consists of buoyancy raft, piled-raft and pile

foundation.

5.2 GROUND IMPROVEMENT TECHNIQUES

Typical soil layer at the north part of KCC area consists of clayey silt with interbeded

organic matter up to the depth of 10.0 to 11.0 m from EGL. The unconfined compressive

strength (qu) of clayey silt and organic clay layer remain in the range of 22 to 71 kPa and

10 to 12 kPa, respectively. The permeability of the clayey silt and organic clay layer

obtained from Taylor's method was found in the range of2.58 to 7.77 x 10-9mls and 5.89

to 8.59 x 10-9mis, respectively. Below this clayey silt soil, there exists c-«f>soil layer.

The option of soil improvement may be stone column, sand pile, mat with khoa mattress,

Rammed aggregate pier (RAP) and preloading with vertical drain for the construction of

low. to medium-rise building structures. In presence of low confining pressure in the

upper layer, stone column and sand pile may bulge excessively. Therefore, these options

were dropped from consideration.

A residential 6-storey frame structure building with 12'-0" to 15'-0" span was assumed

for rough estimation for column loadings. The plan of this frame structure, elevation of

different types of foundation, assumption to calculate settlement and relevant data have

has been shown in Appendix-F. The unfactored interior column load was 270 kip. For this

98

column loading, the total settlements of individual pad footing, mat and mat with Khoa

--t mattress were 11.12 inch, 3.71 inch and 2.93 inch, respectively.

Maximum allowable settlements for isolated column footing and mat foundation have

been shown in the Table 5.1. From this table, it is found that mat with Khoa mattress may

he acceptable according to.Skempton and McDonald (Das, 2005).

Table 5.1 Maximum allowable total settlements for different types of shallow foundations

Types of foundations Sources

Skempton and Bowles (1997) BNBC(1993)

McDonald

(Das, 2005)

Total settlement (mm) of 45 25 25

isolated footing in clay (not mentioned (not mentioned soil

soil types) types)

Total settlement (mm) of 76-127 50 50

mat in clay (not mentioned (not mentioned

soil types) soil types)

.,

5.2.1 Preloading with Vertical Drains

Preloading with vertical drains is considered for ground improvement because

(a) interbeded organic matter increases the permeability of the clayey silt layers

(b) presence of c-<j>soil below the upper layer and sand bed placed above the

vertical drain may act as a natural drainage medium under the surcharge

loading

(c) vertical drain may shorten drainage path and facilitate horizontal flow to drain

out pore water.

The arrangement of preloading with sand drain has been shown in Figure 5.1. Surcharge

loading against shear failure was 2.5 m earth filling. The square pattern of sand drain

with 400 mm diameter was taken for calculation. It was found that sand drain should be

placed at 1.25 m interval to attain 91 per cent primary consolidation for the time period of

6-month. Relevant assumptions, data and calculations have been shown in Appendix-F.

99

r~.'\ e~

N

e CD0.,;

e 0 Cu=10kPa'"e @ Cu=71 kPaqN

e <3) Cu=68kPa:;j

Figure 5.1 Typical preloading with sand drain for North

part of the KCC area.

""'%'~ The advantage of this ground improvement technique is that it is very economical. The

ordinary or semi-skilled labours are available locally to execute the sand drain. Special

type of equipments is not required.

The disadvantage is that this system requires extra time for consolidation than other

methods. Sincere effort is required to wash the boring perfectly, otherwise the thick film

of clay-mud will adhere to the borehole walls which may lead to reduce the permeability

adjacent to the vertical drain. In case of prefabricated vertical drains, special types of

equipment are essential and skilled manpower is required. Past experience of the vertical

drain reveals that the project area smaller than 15 katha or 1000 m2 may not economical.

5.2.2 Rammed Aggregate Pier (RAP)

Rammed aggregate pier (RAP) may be one of the best foundation improvement

techniques because of the following reasons:

(a) during the densification process, stone chips is pushed laterally into the sidewall

of the cavities and the soil surrounded the piers are stressed laterally. Since the

sidewall of the cavities is non-uniform, the bond between RAP and the soil matrix

will be more effective.

100

(b) below the footing area 35% or more area is covered by RAP i.e. a great portion of

the organic clay is replaced by the crushed stone and the remaining portion of it is

strengthen by RAP construction. These combined actions causes an increase of the

confining pressure of the matrix soils, thus providing additional load carrying

capacity of the RAP

Typical RAP and the surrounding soil properties within the KCC area has shown in

Figure 5.2.

CD day silt CcrO.26e>=O.95Ca=O.0037

day silt Cc=1.95, Ca=O.022 I'eo=3.11

silty day CcrO.38, Cot = 0.00181e>=1.58

@ silty day CcrO.54, Cot = 0.00191e>=O.78

Figure 5.2. Typical Rammed aggregate pier for the KCC area

If it is possible to attain the stiffness modulus of Geopier or Rammed aggregate pier

(RAP) is at least 108 kitf . The settlement of the upper layer has reduced drastically to

the value is only 1.03". Calculations have been shown in Appendix-F.

The advantage of this technique is that it is very economical. This method can be used in

...,;t- the city urban area without using shorepile and causing other problems. It is very faster

method of construction

The disadvantage is that casmgs are required for caving soil conditions. Normally

consolidated soft clays that extend more than 30 feet below the ground surface can not be

improved due to equipment restrictions. High ground water also causes compaction

problem.

101

5.3 FOUNDATION SYSTEMS

5.3.1 Buoyancy Raft Foundation System

In the south part of the KCC area, buoyancy raft foundation is suitable for small to

moderate rise building, which has concentric loading. The bottom of base slab should be

rest at the below of organic layer. To ensure this, deep excavation may be required. Deep

excavation with high water table in urban areas may create serious problems that may

lead to limit its usage. Another important issue is that this foundation system must be

waterproof. Waterproof can be ensured through reduced permeability and quality of

concrete.

Since the presence of organic layer in the north part of the KCC is at the deeper layer, the

base of the buoyancy raft foundation should be rest at as close as the existing ground

level. In that situation, partially compensation foundation may be yielded. Partially

compensated foundation may also be economical depending on structural grid and type of

structural loads.

5.3.2 Piled Raft Foundation

Since below the organic clay, geotechnical properties of the underlying layer is showing

better in respect of shearing strength and compressibility properties. In case of tall

building where basement is required for car parking or storage, piled-raft foundation is

economical solution for the KCC area. In urban areas, pile- raft foundation can be

constructed by top down method.

5.3.3 Pile Foundation

Pile foundation may be used to transmit the super structure load to the firm strata The

total capacity of a pile is due to both end and side resistance. Where the soil layer at

greater depth consists of dense layer, the cast in situ pile may be expected to have better

load resistance than driven piles. In case of friction pile, effective stress approach is better

representative than empirical approach based purely on undrained shear strength because

skin friction is a function of normal effective stress and interface friction angle. Two

cases may be experience in the KCC area for pile foundation. The two cases are:

102

~j.., (

I.

(a) Piles through compressible strata into stiff clay

(b) Floating pile in deep soft deposite

(a) Plies through compressible strata into stiff clay

Under these conditions most of the load on the piles is carried ultimately by the points.

This produces a large concentration of stress in the clay near the point of each pile. The

results of a load test on a single pile may be perfectly reassuring, because the major part

of the load during the test is carried by skin friction, and the consolidation of the clay near

the pile points develops very slowly. However, as time goes on, the settlement due to this

consolidation may become very large. The spacing of the piles should not be less than 3d,

to reduce as much as possible the disturbance of the clay constituting the bearing stratum.

A spacing of 3.5d is preferable.

(b) Floating pile in deep soft deposite

The factor of safety for the pile groups with respect to a base failure should be equal to 2

to 3. The ultimate bearing capacity of a friction pile group increases with increasing

spacing. Furthermore, at a given load per pile the settlement of a cluster consisting of a

given number of piles decreases as the spacing increases.

103

,,.

~CHAPTER6'

CONCLUSIONS AND RECOMMENDATIONS

6.1 GENERAL

The findings of the geotechnical characteristics and the suitable ground improvement

'techniques as well as relevant foundation systems for the study area are described in this

chapter.

-,Y'" .~' ,

',6.2 GEOTECHNICAL CHARACTERISTICS OF THE KCC AREA SOIL

In the present study the KCC area has been divided into two parts: north part and south part.

. South part is further divided into two areas: non-riverside area and riverside area. The north

part consists of Goalkhali and Khalishpur area. The south part non-riverside area comprises

of Chotta Boyra, Sonadanga, and Farazipara area while the Rupsa Fery Ghat represents the

south part riverside area.

The analysis of the index properties reveals that the upper layer of 6.0 to 7.0 m depth in the

north part consists of elastic silt formation. The organic layer from 7.0 to 8.5 m depth

~. contains 13.00 % to 41.44 % organic matter. The layer from 8.5 to 19.0 m depth consists of

elastic silt to silty clay, which is underlain, by fat clay with little organic matter up to 30.50m depth.

On the other hand, the upper 3.0 to 4.0 m depth from EGL in the south part non-riverside

may be classified as fat clay to silty clay in which 34 % to 55 % particles are colloidal. The

organic layer from 4.0 to 5.0 m depth at south non-river side area contains 32.74 % to 43 % . ,

.:organic matter. The layer from 5.0 m to 13.0 m depth consists of elastic silt with fine sand,

which is underlain, by silt with fine sand and mica up to 30.5 m depth. The top 12 to 13 m

104

depth from EGL of riverside area in south part consists of clayey silt (ML/CL). The layer- .

between 13 and 21 m depth from EGL is elastic silt (MIl) in nature. The layer betweeri'21

","" and 30.50 m depth from EGL may be identified as silt (ML) with mica.

,i

The specific gravity of inorganic clay, organic clay and inorganic silt remains in the range' of

2.58-2.86, 1.61-2.29 and 2.60-2.82, respectively. The observed values were found to conform

to the usual range of values. The natural moisture content of inorganic silt or clay and

organic clay ranges from 31.30 % to 52.10 % and from 157 % to 212 %, respectively. The

degree of saturation of the inorganic soil samples ranges between 81.40 % and 98.60 %.

However, the degree of saturation of organic soil samples was found to be 100 %. This is

because ground water level is located almost at the ground surface.

The liquid limit and plastic limit for inorganic soil samples vary from 31% to 79 % and 16 %

~ to 40 %, respectively while the liquidity index varies in the range of 0.17 to 0.83. These

values of Atterberg limits compare well with the usual range of values. However, for organic

clay samples, the liquid limit and plastic limit were found to vary form 109 % to 114 % and

55 % to 57 %, respectively while the liquidity index values remain in the range of 1.13 to

2.73. Such high values of Atterberg limits and liquidity index of the organic layer sugg.~1sts

potential difficulty for foundation design and construction within the study area.

For the upper 2.67 to 10.29 m depth layer, for the SPT N-value varying between 1 and 7the

unconfined compressive strength values of the undisturbed inorganic soil samples vary from

7.0 to 119.0 kPa. No unconfined compressive strength of organic soil 'samples could be

~~ determine because of the difficulties involved in specimen preparation in the laboratory.

However, liquidity index of the organic soil samples indicate that the organic layer in the

study area is likely to exhibit very low shear strength. The shear strength properties, c and

4> values of the disturbed silty soil samples collected from 19.81 to 28.95 m depth remain in

the range of7.0 - 52.0 kPa and 24-34 degree, respectively.

The compression index of inorganic silt and clay layer varies from 0.17 to 0.67 while the

compression index for the organic layer remains in the range of 1.95 to 4.01. The coefficient

105

of secondary compression index for inorganic clay and silt remains in the range of 0.001 to

0.0075. The coefficient of consolidation for inorganic clay and silt layer remains in the range

~, of 3.12 to 6.98 m2/yr while the coefficient of consolidation for the organic layer remains in

the range of22.70 to 25.10 m2/yr, for an effective pressure 50-100 kPa.

The coefficient of volume compressibility, mv values for inorganic soil samples remains in

the range of 0.3408 to 0.6240 m2/MN while the mv values of organic soil samples remain inthe range of 0.8210 to 1.220m2/MN.

6.3 GROUND IMPROVEMENT TECHNIQUES

Preloading with sand drain may be the suitable foundation solution .for the north part i.e.

'f Goalkhali and Khalishpur area. Because the permeability of the clayey silt or silty clay layer

in the Goalkhali or Khalishpur area is relatively high. Moreover, organic layer and water

table are relatively below from the EGL. This method may not be effective in the south part

i.e. Chota Boyra, Sonadanga, Farazipara and Rupsa area. The reasons are presence of upper

organic layer and interbeded organic material and existence of high ground water table.

The Rammed aggregate pier (RAP) may be the most suitable ground improvement technique

for both north and south part of KCC area for low to medium rise building structures. The

causes of its suitability are based on that very stiff aggregate piers are installed in cavities

which are filled with crushed stone in a number of layers and densified very small layer with

high-energy impact rammer. During the densification process, stone chips is pushed laterally

~ into the sidewall of the cavities and the soil surrounded the piers are stressed laterally. These

combined actions causes an increase of the confining pressure of the matrix soil though the

soil layer comprises of interbeded organic matter.

6.4 FOUNDATION SYSTEMS

Piled raft foundation system may be suitable for tall building where basement is required for

car parking or storage purposes. This method may be applied only for north part. Since the

106

upper layer of the north part is soft to medium stiff clay, the raft placed on this layer may

carry a substantial portion of super strueturalload.

Pile foundation may also be employed for tall building where basement is not required or in

situations where excavation for raft is troublesome due to presence of adjacent buildings.

6.5 RECOMMENDATIONS FOR FUTURE STUDY

Presence of mica content in the deeper layers of the KCC area reduces the shear strength of

the soil significantly. No parametric study of the effect of mica content on soils shear

strength was undertaken in this work. Therefore, a rigorous study on this topic isrecommended.

'..•...\ Determination of Young's modulus, E, shear modulus, G and Poissons ratio, v, of the soil

layers were not included in this study. These properties based on empirical relationship may

not be representative for the study area. Therefore, these properties can 'be determinedthrough further study.

Since the KCC area soil possesses very low permeability, it may be necessary to create

vacuum pressure within the drainage bed for successful implementation of preloading with

vertical drain. Intensive study is required on this ground improvement technique.

The skin friction around the pile shaft is estimated in terms of undrained shear strength ofthe

soil by means of an empirical factor. But appropriate value of skin friction will depend not

only on the shear strength of the soil, but also on its past stress history and overconsolidation

ratio. As the effective overburden pressure ofKCC area soil substantially changed due to the

presence of interbeded organic content, further study is required to estimate exact skinfriction.

.. I

107 ! .

Reference:

AASHTO (1993) "Standard Method of Test for Determination of Organic Content in Soilsby Loss on Ignition", Designation: T267-86, pp. 840

Alam, M.K., Hassan, AK.M.S., Khan, M.R. and Whitney, J.W. (1990) "Geological Map ofBangladesh", Geological Survey of Bangladesh Publication, Dhaka.

Al-Khafaji, AW. and Anderson, O.B. (1992) "Equation for Compression IndexApproximation", JGED, ASCE, Vol. 118, No.1, Jan., pp. 148-153.

Asaoka, A (1978) "Observational Procedure of Settlement Prediction", Soils andFoundations, Vol. 28, NO.4, pp. 87-101.

ASTM (1984) "Annual Book of ASTM Standards", Vol. 04.08.

Azzouz, AS. (1976) "Regression Analysis of Soil Compressibility," Soils and Foundations,~_ Tokyo, Vol. 16, NO.2, pp. 19-29. '

",

Bangladesh Bureau of Statistics (2001), "Statistical Year Book", 22nd Edition, PlanningDivision, Ministry of Planning, Government of the People's Republic of Bangladesh,pp.25.

Bearing Capacity of Soils (1994) "Technical Engineering and Design Guides as Adaptedfrom the US Army Corps of Engineers, NO.7", New York, ISBN 0-87262-997-X, pp.6-8.

BNBC (1993) "Bangladesh National Building Code", Housing and Building ResearchInstitute, Mirpur, Dhaka 1218, ISBN 984-30-0086-2, pp. 6-79. "

Bowles, J.E. (1978) "Engineering Properties of Soils and Their Measurement," 2nd Ed.,McGraw-Hill, New York, pp. 61-67 .

..,( Bowles, 1.E. (1997) "Foundation Analysis and Design," 5th Ed., McGraw-Hill, New York,pp.15-165.

BRTC (2003) "Report on Causes of Differential Settlement and Suggestions for RemedialMeasures of Two 4-Storied Buildings of Khulna Medical College," Department ofCivil Engineering, Bangladesh University of Engineering and Technology, Dha~-1000, pp. 3-6.

British Standard 6399 (1975) "Code of Practice for Dead and Imposed Loads", Part 1,British Standard Institution, pp. 24-26. 'I

British Standard 1377 (1975) "Determination of the Specific Gravity of Soil Particle(Organic Soils)", Note-3 on Test 6(A), pp. 26-29. ; .""

.' ~108

)i

\

BWDB (2000-2005) "Weekly Ground Water Table", Hydrology Wing, Bangladesh WaterDevelopment Board, Dhaka.

Charles, J.A. and Skinner, H.D. (2004) "Settlement and Tilt of Low-Rise Buildings", Proc.,of the Institution of Civil Engineers-Geotechnical Engineering, Vol. 157, No.2, pp.65-75.

Cernica, J. N. (2005) "Geotechnical Engineering: Foundation Design," John Wiley and Sons,New York, pp. 8-9 and pp. 399-403.

Cunha, R.P., Poulos, H.G. and Small, J.e. (2001) "Investigation of Design Alternatives for aPiled Raft Case History", Journal of Geotechnical and GeoenvironmentalEngineering, Vol. 127, No.8, August 2001, pp. 635-641.

Curtin, W.G., Shaw G., Parkinson, G.I. and Golding, J.M. (1994) "Structural FoundationDesigner's Manual", UK, pp. 290-293.

~, Das, B.M. (1985) "Advanced Soil Mechanics", International Student Edition, McGraw-Hili" Book Co. (Singapore), ISBN 0-07-015416-3, pp. 260-262.

, iDas, B.M. (1990) "Principles of Foundation Engineering", 2nd Edition, PWS-KENT

Publishing Company, Massachusetts, pp. 217-226.

Das, B.M. (2005) "Principles of Foundation Engineering", 5th Edition, Eastern Press(Bangalore) Pvt. Ltd., Bangalore, pp. 171-176.

Design of Pile Foundations (1994) "Technical Engineering and Design Guides as Adaptedfrom the US Army Corps of Engineers, No.1", New York, ISBN 0-87262-930-9, pp.17-21.

Farrell, T. and Taylor, A. (2004) "Rammed Aggregate Pier Design and Construction inCalifornia-Performance, Constructability and Economics", SEAOC, Convent ibnProceedings.

Fleming, W.G.K., Weltman, AJ., Randolph, M.F. and Elson, W.K. (1992) "PilingEngineering", 2nd Edition, Surrey University Press, London.

Fox, N. S. (2000) "Case Histories of Rammed Aggregate Pier Soil ReinforcementConstruction Over Peat and Highly Organic Soils", Geopier Foundation Company,Inc., Arizona, USA.

Fox, N.S. and Cowell, MJ. (1998) "Geopier Foundation and Soil Reinforcement Manual",Geopier Foundation Company, Inc., Scottsdale, Arizona.

Gibs, HJ. and Holtz, W.G., (1957) "Research ort Determination the Density of Sands bySpoon Penetration Testing", Fourth International Conference on Soil Mechanics andFoundation Engineering, Vol. 1, pp. 35. .

109

I

Handy, RL. (2000) "Does Lateral Stress Really Influence Settlement?", Journal ofGeotechnical and Geoenvironmental Engineering, ASCE, Paper submitted' forpublication.

Hossain, M. M. and Rahman, M. N. (2005) "Sub-Soil Investigation Report at the ProposedSite for the Construction of Residential Building of S.I & A.S.I at Sonadanga Thana,KMP, Khulna", Department of Civil Engineering, KUET, Khulna, pp. 7.

Horikoshi, K. and Randolph, M.F. (1998) "A Contribution to Optimum Design of PiledRafts", Journal of Geotechnique, Vol. 48, NO.3, pp. 301-317.

Hossain, M. 1. (2007) "Performance Study of Rammed Aggregate Pier as a GroundImprovement Technique in Soft Ground", M.Sc. thesis, Department of CivilEngineering, Khulna University of Engineering and Technology, pp. 46.

Hulse, R and Mosley, W.H. (1986) "Reinforced Concrete Design by Computer", MacmillanEducation Ltd, UK, pp. 288.

IImpe, W.F.V. (2001) "A Report Prepared on Behalf of Technical Committee TC18 on Piled-~. Foundation", Methods of Analysis of Piled Raft Foundation, In~ernational Society of

Soil Mechanics and Geotechnical Engineering.i

Islam, M.S., Hoque, E and Munshi, M.M.K. (2003) "Geotechnical Characteristics of a PeatySoil in Bangladesh," 2nd International Conference on Advances in Soft SoilEngineering and Technology, 2-4 July 2003, Malaysia.

Kraft, L.M. (1982) "Effective Stress Capacity Model for Piles in Clay", Journal of.Geotechnical and Geoenvironmental Engineering, ASCE, Vol. 108, No. GTll,pp.1387-1404.

Kabir, M.H., Alam, MJ., Hamid, A.M. and Aktaruzzaman, A.K.M. (1997) "Foundations onSoft Soils for Khulna Medical College Buildings in Bangladesh", Civil EngineeringDepartment, Bangladesh University of Engineering and Technology, BUET, Dhaka.

Khulna Master Plan (2001) "Structural Plan, Master Plan and Detailed Area Plan for KhulnaCity", Khulna Development Authority and ACQUA-SHELTECH Consortium.

Kopula, S.D. (1986) "Discussion: Consolidation Parameters Derive from Index Tests,"Journal of Geotechnique, Vol. 36, NO.2, pp. 291-292.

Ladd, C.C. (1967) "Strength and Compressibility of Saturated Clays", Pan American SoilsConference, Caracos, Venezuela.

Lee, I.K., White, W. and Ingles, a.G. (1983) "Geotechnical Engineering", Pitman PublishingInc., Massachusetts, pp. 346-350. P:

Mesri, G. (1990) "Post Densification Penetration Resistance of Clean Sands," JGED, ASCE,Vol. 116, GT 7, pp. 1095-1115.

110

"'~

{

Meyerhof, G.G. (1974) "Penetration Testing Outside Europe: General Report," Proceedingsof the European Symposium on Penetration Testing, Vol. 2.1, pp. 40-48.

-~,

Morgan, J.P. and McIntire, W. G. (1959) "Quaternary Geology of the Bengal Basin, EastPakistan and India," Bull. of the Geology, Society of America, pp. 319-342.

Munshi, M. M. K. (2003) "Geotechnical Characterization of Soft Soil along Mollahat-Noapara Road Section at Bagerhat," Department of Civil Engineering, BangladeshUniversity of Engineering and Technology, Dhaka, pp. 9-11.

Murthy, VN.S. (1993) "A Text Book of Soil Mechanics and Foundation Engineering", SaiKripa Technical Consultants, India.

Nakase, A. (1988) "Constitutive Parameters Estimated by Plasticity Index," JGED, ASCE,Vol. 114,No. GT 7, July, pp. 844-858.

NAVFAC (1982) "DM7.1, Soil Mechanics", U.S.Department of the Navy, Naval FacilitiesEngineering Command, 200 Stovall Street, Alexandria.

Nishida, Y. (1956) "A Brief Note on Compression Index of Soils," JSMFD, ASCE, Vol. 82,SM 3, July, pp. 1-14

Peck, R.B., Hanson, W.E., and Thornburn, T.H (1974) " Foundation Engineering," JohnWiley and Sons, Ltd., New York.

Poulos, HG. and Davis, E.H (1974) "Elastic Solutions for Soil and Rock Mechanics", JohnWiley and Sons, New York.

Poulos, HG. (2001) "Piled Raft Foundation Design and Applications", Journal ofGeotechnique, Vol. 50, NO.2, pp. 95-113.

PWD (2000) "Abu Naser Hospital Project at Goalkhali, Khulna ", Design Divsion-3, Dhaka.

PWD (2006) "600 sft Residence for SI and ASI at Sonadanga Thana Compound, Khulna",Design Division-6, Dhaka.

Randolph, M.F. and Worth, c.P. (1979) "An Analysis of the Vertical Deformation of PileGroups", Journal of Geotechnique, Vol. 29, NO.4, pp. 423-439.

Randolph, M.F. and Worth, C.P. (1981) "Application of the Failure State in UndrainedSimple Shear to the Shaft Capacity of Driven Piles", Journal of Geotechnique, Vol.31, No.1, pp. 143-157.

Randolph, M.F. (1983) "Settlement Considerations in the Design of Axially Loaded Piles",Ground Engineering, Vol. 16,NO.4, pp. 28-32. .

111

Razzaque, A and Alamgir, M. (1999) "Long-Term Settlement Observation of a Building in aPeat Deposits of Bangladesh," International Conference at AlT, Thailand.

-1. Reul, O. and Randolph, M.F. (2004) "Design Strategies for Piled Rafts Subjected to NonUniform Vertical Loading", Journal of Geotechnical and GeoenvironmentalEngineering, Vo. 130,NO.1, pp. 1-13.

Sanglerat, G. (1972) "The Penetrometer and Soil Exploration", Elsivier Publishing Co.,Armsterdam.

Serajuddin, M. (1998) "Some Geotechnical Studies on Bangladesh Soil: A Summary ofPapers Between 1957-96," Journal of Civil Engineering, the Institution of Engineers,Bangladesh, Vol. CE 26, NO.2, 1998. pp. 101-125.

Serajuddin, M. and Chowdhury, M.A (1998) "Correlation between Standard PenetrationResistance and Unconfined Compressive Strength of Bangladesh Cohesive Dep6sits",Journal of Civil Engineering, the Institution of Engineers, Bangladesh, Vol. CE 24,NO.1, 1996. pp. 69-81.

-r- Serajuddin, M. and Ahmed, A (1982) "A Study of Some Engineering Properties of SoilsOccurring in Different Regions of Bangladesh", Proc. Seventh Southeast AsianGeotechnical Conference, pp. 853-86.

Settlement Analysis (1994) "Technical Engineering and Design Guides as Adapted from theUS Army Corps of Engineers, NO.9", New York, ISBN 0-7844-0021-0, pp. 45.

Siddique, A, Safiullah, AM.M and Ansary, M.A (2002) "Characteristic Features of SoftGround Engineering in Bangladesh, Coastal Geotechnical Engineering in Practice",Nakase and Tsuchida (edu), ISBN 905809151 1, pp. 231~248.

Sing, A (1992) "Modern Geotechnical Engineering," CBS Publishers & .Distributers. Pvt.Ltd, India.

Skempton, AW. (1951) "The Bearing Capacity of Clays", Proc. British Bldg. Research.A{ Congress, 1 pp. 180-189.

Skempton, AW. and MacDonald, D.H. (1956) "The Allowable Settlement of Buildings",Proceedings Institution Civil Engineers, Vol. 3, NO.5, pp. 727-784. 'I .

SPARRSO (1999) "Generalized Land Use Map ofKhulna City (Master Plan) Area", Dhaka.i

Sowers, G.F. (1953 and 1962) "Modern Procedures for Underground Investigation",Proceedings, ASCE.

Stamatopoulos, AC. and Kolzias, P.C. (1985) "Soil Improvement by Preloading", JohnWilley and Sons, Inc., USA, pp. 208-229.

112

Tan, Y.C, Chow, C.M. and Gue, S.S. (2004) "Piled Raft with Different Pile Length forMedium-rise Buildings on Very Soft Clay", Gue and Partners Sdn Bhd, KualaLumpur, Malaysia.

Terzaghi, K. and Peck, R.B. (1967) "Soil Mechanics in Engineering Practice," 2nd Ed., JohnWiley and Sons, New York, pp. 729.

Terzaghi, K., Peck, R.B and Mesri, G. (1996) "Soil Mechanics in Engineering Practice," 3rdEdition, John Wiley and Sons, New York, pp. 431-435.

Tomlinson, M.J.(1957)" The Adhesion of Piles Driven in Clay Soils", proc. 4th Int. Conf. onSoil Mech. and Foundation Engineering, Vol. 2, pp. 66-71

Tomlinson, MJ. (2001) "Foundation Design and Construction", 7th Edition, Pe~rsonEducation Ltd., England, UK, pp. 186.

Varghese, P.C. (2005) "Foundation Engineering", Prentice-Hall oflildia Pvt. Ltd., Delhi, pp.295-296.

.~ Weltman, A.J. and Healy, P.R. (1978) "Piling in Boulder Clay and Other Glacial Tills", DoEReport PG. 5, London.

Wu, A.ll. and Scheessele, D.J. (1982) "A Cost-Effective Shallow' FoundationAccommodates Three Feet of Settlement", ASCE, Vol. 53, No.3, pp. 65-67.

113

APPENDICES:

APPENDIX-A: Record of Subsurface Exploration

APPENDIX-B: Grain Size Distribution Results

APPENDIX-C: Unconfined Compressive Strength Test Results

APPENDIX-D: Direct Shear Test Results

APPENDIX-E: Consolidation Test Results

APPENDIX-F: Calculation of Different Types of FoundationSystems

114

APPENDIX-A(Record of Subsurface Exploration)

115

Record of Subsurface ExplorationProject Name

Project Location

Boring Method

Shelby Tube

MSc. Research Project

South CmlraJ Road, Khulna

Wash boring01)=2", ID = I i"

Boring no. 0 I

Apparent ground water table ....Q2..!!!.Date Completed 25.07.05

Date Started 25.0705

~,o£i

SOIL CLASSIFICATION ~ " .....•• 0u

~g g> til Z-;;;] o£i ti:j1;1

~Subsurface Elevation (2.71 m) &Itil tIl~

27.43 -:-:: 7.43

LEGEND:

~Soft Clay

• Organic matter

ITill Silt with fine sand

~ Fine sand .

m Silty clay

~ Clayey silt

Ei Clay with Organic malter {

8 Silty fine sand

El Silt with Organic matter..

..•.. Ground Water Level

SAMPLE:

o Disturbed Sample

• Un-disturbed Sample

N=50,over; 26 blows to 2" penetrate

"

I '

I I1JI I~=IJ\ IIN120!t2lLt: :,t,

,

!*31! I+31~ ~JF21~ ~i i~ ~

Nil I~ ~

J21i ~

+31! !i iJ.21I I1=51I 1J=5!! I

4.27

Silty fme saod with trace mica;light Grey. dmse stratified soillaye:t.

Silt with fine sMd and traces f orgnicmaller, Grey colour.

Very soft organic clay. deep Blac!.:colour, very bad odour; moist

Clayey silt with traceorganic maller. deepBrown colour. mois!.

Very soft clay with traceorganic malter. very deepBrown colour. moist.

Very soft clay with traceorganic malter, very deepBro",n colour. moist.

~.

116

Record of Subsurface ExplorationProjectNamc

Project Location

Boring Method

Shelby Tube

M. Sc. Research Project

South Centml Road, Khulna

WAShboring01)02", ID= If'

Boring no. 02

Ground Water Table 0.152 m

Date Completed 26.07.05

Date Started 26.07.05

SOIL CLASSmCATION

SuOOurfllCeelevation (2.71 m)

Very soft clay with lenlceorganic maller, very deepBrown colour, moist

Very soft organic clay, deep Black colour,very bad odour; moist '

Silty clay with trnce organic maller.deep Brown colour, moist

Clayey silt with trllCe organic mailerBrown colour, moist

Sih with fmc sand and trnces of orgnicmaller, Grey colour.

Silty fine sand with trace mica. light Greydense stratified soil layer.

!I'"

14.63 :.:.:.:.:.:.

21.94 :::::

117

~oZ';;.~b::.s",Ill

10 30,~ :

~ i»=41 1

11,1 IN2 != Ii".i iJ=11

JI

i I~Nt12~

Lli i: i

iI

LEGEND:

~Soft Clay

• Organic Matter

~ Silt with few sand /......'"

~ Fine Sand

19 Silty Clay

~ Clayey silt

EE Clay'~th Organic Maller

~ Silty fine sand

bl Silt with Organic Matter,.

... Ground Water Level

SAMPLE:

0 Disturbed Sample

• UtHIistmbed Sample


Project Location

Boring Method

Shelby Tube

M.Sc. Research Pnjccl

Rupsha F. Ghat

WashboriJ'll!00=2",10=1'

Boring no. 03

OrOlmd Water Table ~

Date Completed 27.07.0S

Date Started 27.07.05

SOIL CLASSIFICATION

Subsurface Elevation (I.g3 m)

Clayey silt with trace organic maller,deep Brown col", •., moist

Clay with OIl"anicmaller,deep Black, moist.

Silt with fme sandGray in colot •.

Silt with clay IItld OIl"lDUCmaller,deep Grey, stratifIed layer.

Silt with fme slltld and traces of mica

LEGEND:

~SoflChlY

• Organic Maller

mEl Silt with fine sand

~ Fine Sand

lIm Silly Clay

~ Clayey silt

sa Clay with Organic Malter

~ Silly fine sand

Ed Silt with Organic Malter"

yo Ground WaterLevd

SAMPLE:o Disturbe,d Sample


N=50


Project Location

Boring Method

Shelby Tube

M.Sc. Research ProjectRupsha F. Ghat

Wash boringO0=2",tO=lt

Boring no.

Ground Water Table

Date Completed

Date Started

040.4601

~807.05

~8.07.05

son. CLASSIFICATION

Subsurface Elevation (1.83 01)

Clayey silt with trace organic matter.very deep Brown colol •.•moist

Clayey silt with mica. medil.m Grey

Silt with CUte.and with tmoesof organic mailer. GTeyoolol•.•medilml de:me.

LEGEND:

~Soft Clay

• Organic Maner

t!I Silt with sand

~ Fine Sand

11m Silty Clay

~ Clayey silt

ES Clay with Organic Matter

~ Silty fine sand rEl Silt with Organic Matter

"00 f..•. Ground Water Level

SAMPLE:[] Disturbed Sample



Project Location

Boring MethodShelby Tube

M.Sc. 'Research Project

Khulna Medical College

Wash boringOD=2",lDm I'"

Boring no.Orotmd Water Table

DAte Completed

Date Started

050.6tm

290705

29.07.05

...~

SOIL CLASSIFICATION

SuoolDface Elevation (2.04 m)

Very soft silty clay with "'!t"'uic matt••.very deep Brown. bad odour, moist

Very soft orp:anic clay.deep Black colour; very bad odour,moist

Silty clay with mlerbeded orp:anicmalter, "ery deep Brown oolour, moist.

Clayey silt with orp:mncmatt••.•deepOrey

Clayey silt with mica. meditmt Brown

i'"!

30,48

120

LEGEND:

~Soft Clay

• Organic Mauer

E$J Silt with few ssnd

~ Fine Sand

lIm Silty Clay

~ Clayey silt

Ei3 Clay with Organic Matter

~ Silt

/EJ Sill with Organic Matter..

\

.,. Ground WaterLevd

SAMPLE:o Disturbed Sample


Record of Subsurface Exploration

LEGEND:

••• Ground W.terLeve1

Un-disturbed Sample

SAMPLE:Disturbed Sampleo

•

~ SoftClay

• Organic Maller

~ Silt with few sand

~ FineS.ad

~ SiltyClay

~ Clayey sill

Ei3 Clay wilh Organic Matter

~ Silt

~ Silt with OrgaaicMlllter

Clayey silt with mica and trace oforganic matter. meditan Brown

Clayey .ilt with interbeded oqtanicmatter.deep Gray. \vith O.M

Clay with organic mlllter.deep Black. moist.

Silty clay with trace of organic mlllter.vCl)' deep Browllbad odour. moist

Silty clay with trace of orgauic mlllter,vCl)' deep Browllbad odour, moist

Project Name M.Sc. Reseorch project Boring"". 06Project LoaIlicn Khulna Medicnl CoUep;e Gromtd Water Table ....Q;fu!!.Bocing Method Wash bocill/! Date Completed ~O.O7.05Shelby Tube OD=2.,ID~lf

Date Started ~907.05

SOIL CLASSIFICATION ! i '"'d~. IEl 3' '" Z~

-g oS .~Do !i::.9Subsurface E1",'ntiOll (2.04 m) ..

'" 10 Q "'10

121

Record of Subsurface ExplorationProject Name M.Sc, Research Proj<d

Project Localiro KhuIna Po!ytcclmic Institute

~M",hod W•• hboringShelby Tmc 00=2",10=1 f

Boring no,

Ground Water Table

Date Compleled

Date Started

07

0.61 m31.07,05

31.0705

son. CLASSIFICATION t i ..,Q d

~g ~ rn z-1 t . r;

Subsurface Elevatim (3.89 m) £: t:-2rn m Q rnlO

Clayey lilt with interbeded organicmaller, mednnn Grey in colour.

Very lOft organic clay,light BlaC!::colour, llighllybad odour, moilll

Silty clay

Soft Silty clay withinterbeded organicmailer and trace mica,Grey in colour

LEGEND:

~Soft Clay

• Organic Maller

~ Sill wilh few sand......

mm Fine Sand

tIm Silty Clay

~ Clayey lilt

Ei3 Clay with Organic Matter

~ Silt {.~

G] Silt with Organic Matter..

W Ground Water Levd

SAMPLE;

[] Disturbed Sample

• Un-dilturbed Sample

Record of Subsurface ExplorationProject Name M.Sc. Research Project

Project Location K1mlna Polytechnic InstiMe

Boring Method Wash beringShelby Tube OD=2",ID~ Ir

Boring no. 08

Ground Water Table .J!.2!.m..Date Completed 01.08.0S

Date Started 01.0805

SOIL CLASSIFICATION ! j 0gg !l' Z-~ ! .~

Subsurface Elevatiro (3.89 m) tl l;::.2en lQ enlQ

LEGEND:

Un-disturbed Sample

Ground Water Level

Sill

Silt wilhOrganic Matter

Clay with Organic Malter

Clayey silt

Fine Sand

Silty Clay

Silt with few sand

Organic Malter

Soft Clay

SAMPLE:Disturbed Sampleo

•

~•~

~

..JIm"'.

~ ..

53ffiRG

Soft Silty clay withinterbeded oqz:mticmatter rotd trace mica,Grey in colour

Soft Silty clay withinterbeded orlt""icmatter, Grey inoolour

vcry soft oqz:anic clay,li[tht Black colour, .li[d~1ybad odour. moist

Clayey silt with interbeded oopnicmatter, meditnn Grey in oolour.

Record of Subsurface Exploration

-+..I

Projecl Name M.Sc. Research P"liectProject Location ;::;: ;,;,1imI H8rtdicndh

Boring Method Wash borD!IShelby Tube 01><=2",10= Ir

son. CLASSIFICATION

SubslDface Elevatioo (1.68 m)

Clayey sill with inlerbeded ~maller, medilD11Grey in ""lour.

Very soft orp;anic clay.lighl Black colour, slighllybad odour. moist

Silty clay withinlerbeded organicmalter. Grey in ""b•.

Clayey sill with inlerbeded ~malter. medilD11Grey in ""k •.•..

Boring no. At~Ground Water Table ..md.tu.-Date Completed O~.0805

Date Slarted O~.08.05

i'"tQ

LEGEND:

~Soft Clay

• Organic Matter

LID Silt with few lIltt1d

mm Fine Sand

E Silty Clay

~ Clayey silt I

EE Clay with Organic Matter \

~ Sill

bl Silt with Organic Matter..

'!r Ground Waler Levd

SAMPLE:o Distutbed Sample

• Un-distutbed Sample

Record of Subsurface ExplorationProject Name M.Sc. ResCllfch Project

Ooftltbali PlfYlIitallbmdicndtlProject Loc:atim ••.•,.,.••.••iP•••LC•••_•••••••• _

Boring Method Wash boringShelby Tube 00=2",10 ~ If

Boring no.GrollJld Water Table

Date Completed

Date Stat1ed

10At ;:n;unamriaee

03.08.05

03.08.05

.J...."

SOIL CL ASSIFICA nON

Subsurface Eleo.'atiOll(L61 m)

Clayey .ilt with interbcdod 0I'[<3Ilic

nlatter. medi\un Grey inoolour.

Very .oft "'ltanic clay.Iij<htBlack colour •• litlh!1ybad odour. moist

Very .oft clay with interbeded.organic matter. "ery deep Brown.bad odour. moist.

Clayey .ilt with interbcdod organicmatter, medi'Jlll Grey inoolour.

Soft Silty clay withinterbeded '''It"''icmatter, Grey inoolour

1- ~ 0 ....Q il 0

~g ~ '" z~-5 .~

~ III il" f-< 0p.-'" Q ",III

LEGEND:

~ SoftClay

• Organic Matter

[I] Sill with rew """d ..

~ Fine Sand

lIm SiltyClay

~ Clayey silt

E!i3 Clay with Organic Matt••.

~ Sill

EJ Sill with Organic Matter

.,. Ground Water Level

SAMPLE:o Di.turbed Sample

• Un-di.turbed Sample

Record of Subsurface ExplorationProject Name M.Sc. Research Project

Pwject Loealion Sonadanga Police Stalion

Boring Method

Shelby Tube

Wash txl£l!1B

olF-~".ID= t/"

Boring no. II

Ground Waler Table ....Q..2.L.!ll.Date Completed 04.08.05

Date SI:uteJ 04 OS 05

4.27

\' ej' deep Black: ••.,ni Je.:om""seJorganic matter with \'(fY bad OOtlur.mOIst. 5.48

SOIL C'1.:\SSIFfC,\ nON

Subsurface EIt."",ltlnn (2 ~nIll)

\" L"f)' sl)fi da~' trace; t.'f t.1rganic math:r.\'L"1)' iJ..:,,1'Bwwn. baJ '~l\Ur. 1lh'lsl

Ycry son day traces l,f organic Illattt.':r."' •."I")" d~ Bro\\n. bad l~our. 1l)(\lst

Clayey silt with in1c:rbooa.i orgalllcmath:r. IIh..'\.hum I.ir",'" III Cllklllr

-5 8& ~ .!! ..,Q .• 0

u u~e en :Z. ~:; .<: • is~- l:ll e. I-< 0"'--en Q enl:ll ~

,

,,

, IN~'I~'~2)

,

iN1=5(i llVer

I.E(]END

~ SofiClay

• Organic Matler

GITl Silt with few saud

~ FillcS.uul

IW Silty Clay

~ Clay.")' silt

Eil Clay with Organic Maller

G Silt

W Silt with Organic Maller

••• Ground Water Level

Silt with traces of mica..1rrcrcntly vcry d1.11.'iClilY"'''

126

25.')

27.4.1

,

N!'5(j,'l\'~r

SAMPl.E:o Disturbed Sample

• lIu.t!ish"l",d Sample

Record of Subsurface ExplorationBoring no. I :

(;r"utld \\'allT Tahle ~

Project Name

Project Location

Roring Method

Shelby Tube

M.Sc. Research Project

St"lnadangil 1\)IIC~St.,th'll

1V.'L,h b,'nng00"2". Ill" If Date Started

(15 ON \15

(,508 (15

,U7

127

SAMI'I.E:o Disturblld Sample

• Un-disturbed Sampl~.

LEGEND:

~Soil Clay

• Organic Maller

[ill] Sill with few salld.......

00 Fine Sand

m Silly Clay

~ Clayey sill

~ Clay with Organic Matter

~ Sill

CJ Silt with Organic Matter..

y Ground Water Level ':r' .

N=50 over

,

N~ ~)(j,'cr

N '5(j O~cr

27..J.'

25tJ1

12.1'

6.1(

-5 8& 1:1' " '"Q '5 0

~g "il CIl Z~6 -" . ~:;; eII C. t-l:J 0 eneIIen'" ~Suhsurfac~ Eh..-\'atlOn (~ 9J Ill)

Yt.'y d~p Bla~k COIt"lUT. S~nlJ

Jo.:f'llllfll'lSc:J ,'rgame I11ltth:r with"l.ory' had txlt"luf. IlWISI. 5...•~

:-;.11with tnll:CS nf 1111l.:a,

,"cry Jense: Ja~'t.'f

\'~' l"t,)f\ c1a~' trace::; ,"f t'rganlC mntter.\'Cry dl"'''' t:lrO\\lI. had .'<Iour. 1Il""l

S(IIL CL\SSIFIC.-\110N

Yay SIJt\ da~' tmeL-OSflf l.'rganh': math:r."a)' de•.." Bro\\n. bad I..xk,ur. 1lh.'lst

('Iayc~' sill with IIlkrht.'\h..-..J tlrgilluc

mailer. Ull.'\IUUll Ull.~' III Cllh,ur

~.j

APPENDIX-BGrain Size Distribution Results

128

-- -- -- - -- - - -.- - -- -- ~ - -- - - - -- - --I- ------ --- -- --- --- ""'"'"-

~_.,. -- .._--_ .... --- -- --- _ .... _ ..-.- ._...... _--_ ...- -- -- --- -- _._- -~--- -- --- ._ .. --_ .. -_ .._ .. ._-_ ..__ ....- - -- - - I---- --- - - - - --- -- - ~ --- -- - - -""<l r--I------1'0-- -- - - -- --- -- --_ ... - - - -- - - -- --- - - - - ._-- - -- - - - --- - ~ -

~-- - -- -- ---- ---._ .. ._----- - -- - --- -- - ----- ---,. - - --- -_. -- --- - --- - -- - r--- ---1-- -- -- -- -- -- --- -- - - - --1-- - --- - - .I.e- - - --- -- --- -- - -- - -- - - --- - - ~I-- ---- -- - -- - - - --

-- -- -- -- ---- -- .-_. - - -I-- - 1- - -- - _. --- -- - - --I- --- ---

100

90_ 80..c..i 70

~ 60iii 50c:l;::: 40-c:~ 30~ 20

10

o10.0000

Fine sandSiltClayColloidal

1.0000

= 10%=20%=20%=50%

Grain Size Distribution CurwBH- 01, Depth = 2.67 m

0.1000

Diameter in mm

0.0100 0.0010

Grain Size Distribution CurveBH-01, Depth=6.10 m

~'"- -1- -- j- -- - -- --- - - - - I-- -,

-- - - --- --- - - -- - --_. -_.- - - - -- -- -- -. - --- -'---'- - ._. "'--- -- .-:- -- _ .._--~~- - -- --- -- --- - --- ------ - -- -- -- - - - ro: -- - - -- -- - - --- -

- --- --- -- --- .- - --,. - _._- -- -- _. ----- - - -- ---~

-- -_._~---- - - . - ...._--

_. -- -_._. '.'- -- ._- --- _._- "--_._" . - -- - - --_. ---.--- -- - - --- ~-_._-- - -- -- --- ---- - --- --- "._-

--- - -- - - - _. -- -- -- -- - - - - -- -- -- --_. - - ~ --- -- - - - -- _.--

- - - - - - - - - - - - - - - - - .- - - - - '" -- -- - - --<:

- -- - _.- - - - -- - - - - - - - - - - - - - - -- .__ . - - - -

-- -- - 1- -- - --- - - -

100

90

80-.c:at 70.; 60>-.A•.• 50•~ 40-8 30•..• 20D.

10

o10.00000 1.00000 0.10000 0.01000

Diameter in mm

0.00100 0.00010 0.00001


=6%=22%=21%=51%

129

N~... ._ . ._- .-._.-. - ~

.. _.. _. ------- _ . .. _. -_. ----- .. - ... .- ----- - - ... ...- ---

._. --_., ..._~_.- . _ .. ..._. -_._- .. - ._ ..- _.__ ._- .. ... -_ ... ._ .._. ... ._-_. _ ...__ . .. .. ... _ ... '---" ..

- - - - - - - - - -. - - - _.- - - - r\. - - - -

.- - ..- -- - -. .- _ .. - ~ -- -- -- - --~-I- -~. - - _. - _. - .__ .- _ .. .. - -1- - -- - - t- .-. - . .-1-1--

- 1- - -- - - - - - -I- - - - ""

"- .. ,

'Q.-. . - -1- - -- .- .- -_. - - - _. . - - - - - - ~

~r- - 0- -- - ..- --.- . - .. --_. --- 1.- -- - -- _. ------ _ .. -- -~ .. - -. - -t--._-

Grain Size DistributionCurveBH- 01, Depth = 10.67 m

100

90•• 80..ctil 70';

60~•.. 50Q)c&;: 40••c 30~Q) 20Q.

10

o10.0000


1.0000

=28%=41%= 11%=20%

0.1000 0.0100

Diameter in mm

0.0010 0.0001 0.0000

... ..- - -~~- - - _. .- - - .. - ---- j- - - - - - - --t-'

- - _. - --- - -1-I~ -1- - - - _. -- _.-- - _. - -.. ... -_. --_.__ . .. .. - _ .. _ .. --- - ... ...... ...._ ... .. -- ..- -_._-- .. .- _.- --

.. ._. - -- --- - - .- "--...- . _. - _ . ..- .- - - .- . -i- .•- - - - _.

. - - - - -- - - - --- ._- _. - - . - - - ,. -I~ -

. -- I- - - - - - - -1.- i- -- - -~~.. .. ... - -- -- _. _. -- -- - - - -- .. _.- _.- .. - .- -,-- _.-

- .. .- ... ... _._._- - .. .- --_ . . .- - --- - ... ... :A.-.- .. - _. -- -- - .- _.- --.. - _. -- _._-_ .. - .. _. _ .. ---.- .. - .- - .---- - .. .. .. .- -- ._..-_. .. _ .. ~~ _ . ... .._- ----.".

-<>

Grain Size Distribution CurveBH- 01, Depth = 19.81 m

100

- 90.cQ 80

J 70~.D 60~~ 50;::- 40c~ 30:. 20

10o

10.00000 1.00000 0.10000 0.01000 0.00100 0.00010 0.00001

Diameter in mm


=52%=26%=7%= 15%

130

Grain Size Distribution CurveBH-02, UD-01, D- 3.05 m

~ I- I- - ._-- ~_._.__ . - - ..•.. --_ ..- -- -- - --- -- .._-- ...-.-_. -- _ ... -- --_._-- - -- ..._- -'-"- -- -- ._._- -- - -- ----- - --- - -- ---"'- - -- " -._-~ .._--_ .. -- -- --- -.-. -_ ..- -- -- -- ._-- " ....._ .

- --- - - - -- ~ -

~- - -- - - ---- - --1- - -- -- -- ---

-- --f-- ---- -- - --- ,-- --_._--- - -- - --_. -- -- - -- I- - 1-

- -- - --- - ---1-- --_ .. - -- -- --- - - - --- - - '<l - - - -- -.....•~- -- - - - -- - - - - - I - - --

-<- - -- - -- - -

- - - --- - --- --_. - - ---_ ..- - -- -

10090

_ 80.cj 70

60~•.. 50CI)

~ 40-5i 302CI) 20a.

10o

10.00000


1.00000

=1%=9%=45%=55%

0.10000 0.01000

Diameter In mm

0.00100 0.00010 0.00001

Grain Size Distribution CurveBH- 02, D= 6.09 m

""""<>

-- ."..-.- -- ...- --- ...._-_ ... -- -~ •.....

S-- -- -_ .._- ---_. - -- -.-- ----- - --- -- ---_...

.._- -- - -- -- ...... ..... - - ..._- -- --- --- .... ---- -- - --- -- _._ ..-

--- -- -_..... -- --- ..._ ...._- - --- --"- .._ .. --- -- --- -- -_ .._-- -- -- --- -- --- -- -- -- - ~_.~

\ --- -

.... -- --'-"-- --- - --- ------ -- -- -- ~_.- - -- -- \ .'_._. - - - --_ .. ------ -- ._ .. --- ~~--'

-- ..--" -_..-." --- --'- -- --- "-~ ----_. - --- -- -'x - ...- --_. - -- --- -- ---

--- ._-_ .. - -- ...... -- .._- -- -- - --- •.... --- ---_.- .... ----)"

. - -- -- - -- - "" I'--- --'.

0-- -- -- --- ----- - - -- .•... -_._-_ . -- -- - - -- ...- -- .__ .. _._ .._ ... - -- -_.~ ..__ .

..

100

90

80

- 70.cI:JI

1 60>-,g 50•..CIIC

-= 40-• .400c

" 3 30•..CIIa.

20

10

o10.00000 1.00000 0.10000 0.01000 0.00100 0.00010 0.00001


=2%=33%=31%=34%

Diameter In mm

131

'-!"-' 100

90

80- 70.ca

J 60>.

.D50~c

-= 40-ce 30A.

20

10

Grain Size Distribution CurveBH-02, 0=10.67 m

~I- ,

-

\'\

.. . - -

n"~

-I---.

~

o10.00000 1.00000 0.10000 0.01000 0.00100 0.00010 0.00001 0.00000


=8%=52%= 15%=25%

Diameter In mm

Grain Size Distribution CurveBH- 02,0=13.72 m

\

.. - 1- - - -

K

.......•-

~ -~

.

100

90

80- 70.cIllI

60"I~ 50

" 40-.-,. c""-I 30

20CL

10

o10.00000 1.00000 0.10000 0.01000 0.00100 0.00010 0.00001 0.00000


Oiametar in mm

=70%=35%= 13%=22%

132

••r Grain Size Distribution CUI"JeBH- 03, UD-1, Depth = 2.67 m

- 1- - - - _. - - --- .. - - -- - .- - - _. - - - - - - .. - - -- _. ----.1- -

1\- - 1-

- - -1- - - 1-- - - -- - - - 1-~

~

- - I-- -

- -- .- -_. - . - --- -_. .. - - - .. ..- ._- --- - .- - -_. - _ . .- ..-

- - -_. -- .. - -- _.- - - - - - ._-- _ .. ... -_. - - ... -- ...- --- ..- - ---j-.,;>-- ::<>-_. .•_. -- - - ... -- .._- ------ .. _.- ---- ---_ . - _. -- - _. - -- - - - t- _. ------

.. _. _. --- .__ . - . .- --- -- - - -- "--- _ . . "'-_. - . _bo- - ------

. - -. -- -_. - - _. -- .__ . - _. _. _. _. . _. l- ._- - - ----. .-- - .- -1--I--I

10090

- 80s::.Q 70

I 60~ 50•..~ 40II:- 30~ 20:. 10

o10.00000 1.00000 0.10000 0.01000

Diameter in mm

0.00100 0.00010 0.00001


=2%=60%= 10%=28%

Grain Size DistributionCUI"JeBH- 03, UD-2, Depth = 4.19 m

""- - - -

-I- - - II-. - - -- -I- t-

. - - _ .1- \ - - - --

.. - .. .. .- ---- .- - -- -- ._. __ .. . - - - _. - _. .._-- --_ . .. - - - .... ----_. - ..- ._. _._--

~..

- -- -- - -- - - - - - ---- f---- - .. . - - -- -- - - - -- - .. .- ---

- _ . ._- - ._. - -- - -- - - .. --_. - ._- - -- - - - - ----- -_. - .- _. -- ---

_. -- I-' ---- - - -.- -_ ..-.- - - .-- _.- - - ..• - ---_ .. - _ .... -- -- _. - ._- ._--'-~- - - - --- -- - - -- - --_. - . - - - - - - ... ..- .---- - -- -_.>-.. -.r-.- - - - - - - -- - - - ~

1009080-s::. 70Q

I 60>-.0 50•..CDc 40=--~ c 30B•.. 20CDDo

10

o10.00000 1.00000 0.10000 0.01000 0.00100 0.00010 0.00001


=6%=68%=9%= 19%

Diameter in mm

133

Grain Size Distribution CurveBH- 03,0-16.76 m

-~- - -1- - - - I-- - - - -

-

-- - \-- - .. - - - -f- - -- - - - t- - t--- --- ._.- _._. __ . --- -- ._.. --_ ... ". _. --- -_ .._-_. - -- -- -- ..,'-._- -- --- -_. .__ .__ ._.. - -- .- ._.__ ._-

... ._- --- ---_.- " -- --- --- -- ._-_." .. -- ----- -- -- - --_ .. ..._-_. -- -- ...- ..------- -- ,,- --- --- -._._-

" -- -" --- __ 0_. - -- -- - -" - - -~ -_. - --- --- ---- - - - --.. __ 0" .. -- --- --- ----

- - - --- - - - - -,-_. - .. -- - - ~. - -- - -- ---- ---- - .. - - -- - -

-- - -- -- ----_. - .. -- -" --- .__ .. -- - - --~_. - "< --- _.- - - - -- --.... -().-- -- - - - - - ------ - -- - --- - -_. R -- - - - - --

~r--- - - -1- - - I-- - " 1- -I--- - -- Fr::r:o -

- - -- - -- ; - - - -_. -- - - 1- - -1- - -- - - - - I--- - - - - -

- - - - ---" - ---- -- - _. - -_. -- ~ --- --- -- - - ---- --

- -- -- -- -_ .. -- ..~_.----- -1\ "_. -_ ..- - -- -- _.-- -_.~ _. - _. -- "---- _. - -- - ---" " ••• +. --- .-.._--. .- -- -_ .. ._•..... -- ---~

~_.

"" --- "-"--, "

_. --- -_ ...__ .- -- "'.- ---- ._--_ ..

"- - _.- _.- ---_. " - - - -- - -- " - - - -- -~ .. .- K-- ._- - - -- --- - - -- _. - ----r-....~- ,,- -- - - - - - - - -- -- -- - - -

- - I I -I- N--\-- - - - -

I-

I-- - --- - -1- - :--

0.00001

0.00001

0.00010

0.00010

0.00100

0.00100

134

0.01000

0.01000

Diameter in mm

Diameter in mm

0.10000

Grain Size Distribution CurveBH- 03, 0-21.84 m

0.10000

=25%=44%=9%=20%

=32%=48%=12%= 18%

1.00000

1.00000

Fine',sandSiltClayColloidal


•..•c~••c8•..•D..

100

90••~ 80'; 70~ 60

5040

302010o

10,00000

100

9080••.c

.5!t 70; 60>-.0 50•..~ 40;;:•• 30c•e 20:. 10

o10.00000


\- --- - - -

~

- - - - - f- - e-- -

- - -- - - --- - - -- - 1-1---- - - -- -- - - - - - --- -- ----- -- -...- '--'"-' --- -- - --- --- -- ... ._--~_.. -- _. --- ._... ---"_. -- -- --- _.-- ----_. --- - -- -_ .. "-----

.- --- - ---- -_ ..•.- -- --- --- "---._. --- -- --_. ---_ .. - --- -- _ ..- _.__ .... - -- -- -- -~--- - - -- -- - ----~

- - --- -- _._. - - --- - --~-- - - :\~ -- - --- --- --- --_. - - -- - -- - --~-- - -- - - - - - - ----- - - --- - - -1- -- - --- ---- - - -1- -

-- -- - - -- -_._- - -- - --- - - - - - - -- -- - - - - - 1- -•......~- -- - -- - - -- - -- -- -- -- - - I- -

- ro- :::::::",..- - - - - - - - - - --1- - -- - - -- - - ~--~

100

90

8070

605040

302010

o10.00000


1.00000

=38%=34%= 10%=18%

0.10000 0.01000

Diameter in mm0.00100 0.00010 0.00001

Grain Size Distribution CurveBH- 04, UD-1, Depth = 2.67 m

'V

- - -- - f\ - - 1- - - -- --- - -I-f-

- ---- "-'- - --- -_ ... -- - -- 1'\ - --.. ---- _. -- ._-- - -- -- _ ..._. --- --- --- --- - ._.-.... -_.- .- -- --- -- -- -- -- ....... --- ....- --- -- -- --- ....._.

-- -- --- - -- --- .._ .. -- -- -- - - -- - - -- -- - - --- - --- - -- - - -- -- --- -- -- -- -- -- - - - - - -- - - -

~-- -- - - -- - I--- -- - - - -

- --- -- -- -- - \-- - - - -1-- ~ -- -- - - - - - - .- --- --- - -- - -

- -- - - - - -- - -- - - -- -- - - - - - -- -->-.

-- - - -~ -

.- -- - .- - - - - --- - I---

100

9080

1: 70j 60

~ 50

! 40-= 30J 20••• 10

o10.0000 1.0000 0.1000 0.0100 0.0010 0.0001 0.0000 0.0000 0.0000


=2%=46%= 16%=36%

Diameter In mm

135

Grain Size Distribution CurveBH- 04, UD- 2, Depth = 4.19 m

v- .- - -- - - 1-- - - - - - - - -_. -- .- _._. - - - . -.-- - -

~-_. _. _. - -- - - - ._- - _. .- - .._.. ---

- -I- -- - - - - -- '\ - - - - - - - - -- -. -- - - - - -- -_. -- -S - - - - - --- - - ---- - - - - --,- .- - - .~.- - - - ._. -- ---- .. - -- -- ._- - _ . ._- -- ---_ .. - ._. - ---- - -_. -.- --- --- -- ---- - - '-- - -- - - - --- - - -- -- -- -1- -_. -- 1- -- -1-- -- - I"- :).", -

~- -- -- - - - - -

-- _. - -- _. - -1- _. 1-- -I-- I-- F;~ --- ....•.- - -- -f-- -- - - - - - I----

100

9080

••-ij, 70.~ 60

~ 50Cii 40c:: 30c~ 20:. 10

o10.00000 1.00000 0.10000 0.01000 0.00100 0.00010 0.00001

Diameter in mm


= 10%=52%= 16%=22%

Grain Size Distribution CurveBH- 04, UD- 3, Depth = 7.24 m

~

~- I--

.

.~

-I-

... -. -_..... - - _ . - --- . .. -- - .- - _. --- -- - - -.- - -. - -- -- ..._..- .-. "--'. .. _ . ._.~ ...- .._ ... - .- .... --- --_ .... .- "-_. -.. -...._-_. .- - ..._- -'"--'-' -. .- .__ . --_.

.- .. - .._- -_.__ . - - - _. --- ---.- - _. ._- -- --_. - - -r'o. --~. _. - - ._ . .-_. _0 __ • ... - -- -- ._-

- ._. - - _._- - - - -- -- _. - -- -- - - -- - ~ - .- - .. -- - _. - -

- - _.---- - - - - - - - - _ ....•.F< -- - - ----- - - - - - - - - ~ ~-- - - - -1- - - -I---- - - - -

0.000010.000100.001000.010000.100001.00000

302010

o10.00000

100

9080

:c 700)1 60~ 50Cii 40clO::••C~GIa.

Diameter in mm


=3%=39%=20%=38%

136

~~0- - - - - - - - c--- - - -- -f--,- -

_.- - _.- - .- - \ - --- -_. -- ,-- --- . - - - - -- - .- -- -. - .-- - - - - -- --- -- - -- .- .- .•- -- -- -- - - - _. -_ . .. -- --_. -- - -- --- --- ---- --_. -- -- .--_._. --- ._. -- ...._- -- - - --- - ---- .- - -- -- '-_.- .....- - - -- - -- .- _. -- .~._- - . -- -_. ._--- . - - --- ---- . -- -_. - .- .. - ----- - _. --_. - - . - -- ---- .- - ._-

"-- -- - - -- -.--- -_.- - -- - --- -- - - --_.-

-+-- - - - ~~

- -- - - -- - - - --

-- - .- -- - - -- ---_. - -- - - -- - - - - - - -- --R •.....~- - - -- -- -- - - - -

i<'

1009080

~ 70o'; 60~ 50~ 40c:: 30cG 202G 10Q.

o10.00000 1.00000 0.10000 0.01000

Diameter in mm

0.00100 0.00010 0.00001

Fine sand = 60%Silt = 42%Clay =6%Colloidal = 12%

Grain Size Distribution CurveBH- 05, Sample UD- 02, Depth = 4.19 m

r--.~- -~

- - - -

-- .- -- --- _ ..._-_._. - - ._.- .--- _ ..._-- - -- _.- _.- _ .._-- - .... - -- ....._. "M. _____ " - . _ .. .,_.. _ .._. ----. .- -- ._- .__._0....- -- .. .-- -_ .. -_+._. ----- _. -- _.. .__ . ..-----_ . --- _."" ..__ .....- .. --- --- .... --"' . -_...__ .

- - ---- .-- -- --i\ --- -- ~-- -- -- ----- . --- --_. ---- - -- - ----- - -~

. - -1- - _.- - - -~

. -

- -_. - - - -- - -- -- - --:>-. -- --f--- - - - - - - -

. - - - - - - - - -- - -

. - -- - -- ---- - -f-- - -- . - - - - -

100

90:;: 80o.;; 70~>. 60.a• 50c;: 40-~ 302:. 20

10o10.0000 1.0000 0.1000 0.0100 0.0010 0.0001


=1%=30%=24%=45%

Diameter in mn

137

Grain Size Distribution CurveBH- 06, Sample UD- 01, Depth = 3.35 m

'"",

~-- -- -- . -. ,. -, -- - - -- - _. - - - - -- -- - - ~- -- - -- . - -, - -- -, ---- - - -, - -- - -, - - - -- - -- -- -- --- ---- -- -- - _.__ . - - - - --, - - - - - -- - - --, - --- - - - -- - --

- --- --, ---,. --, - - - -.- - --- --- ,- -- -- - -- ------ -- --, --, .._-_. - -- - --, -- ..__ .- - - --- - - - - - - -,-- --' - ,- - ---. -.-- ----- -- -, - - --- -- ----- - - -- - ----

- - -- -- - --- - - - -- - ---- --- - - - ~- -- .--- - -- -- -- _._,.- - - - --~

- - - - - - - -

- - - ~ - - - ~ ~

"'-0.-- ---~ - - ---r- - -.0 fo;;;; ,--- - - - --

100

9080-a 70

J 60~ 50

! 40-8 30

:. 2010

o10.0000 1.0000 0.1000 0.0100 0.0010 . 0.0001


=30%=60%=5%=5%

Diameter In mm

Grain Size Distribution CurveBH- qs, Sample UD- 02, Depth = 7.24 m

......-- -- - -- ,- ._--- -- -- - - - --

-'~- - - - - - - --

- - - - --- - -- - - -- --- - -- - - --- - -- - -- - --

-- .__ . ,-, - --- _._ ...- - --"----.-- - - -- .._. --- ---- ._... __ .. ._-------_ ... - .... - ._--- -_._ .. -_._ .... ,,~- . -, -- ._-~-_ .._. .._--_.....(),

- --- ,- - --- ._._.- .-.._"------ . -, -- -- --- ._-_._- ,--,-, - -- - --- -- ---- _ .._-"--_. - ,. - - _._." ...._ .. .,.------~

~-- - -- -- --- - - - - - - - -- --- ---- -- - ---, - - - --- - - - -

-, -- - - - -- -- - -- - - - -- -- - --

- -- --- ,- -I- - --' - - ,- - - -- -- - - -- - - - -- -I- - - --

- --- - - -- - - _. - - - - -- - - - - -- --- - - - - - --

- -, - - - - -- -- -- - ,- -- - r-- -- - - -, ,- --- - - - - - -f- --"

1t\ .

1009080-a 70

1 60~ 50~ 40I;::

1~~Q. 10

o10.0000


1.0000

=3%=32%=25%=40%

0.1000

Diameter in mm

138

0.0100 0.0010

-- -- -- -- --- ---- --.--~. - _. _ .. -_. --~ - - _. - .- -- _.- --~- _ . ... -- -- - -_. -_. ----_.

- - --- I-- - --- -

~- - - - --

.. .- .- .. -- - _._- - - _.- _. - _.- -- -- -- .- -- - - - _. -_.-_ .

- - ..-- _. -- ----- --- ._.~----- --- - ).:-- -- _.-. - --- - - - - --- -- ---'().

- - _. - _. _ . ._----- -'-""'---'" .. .. -- ..... • 0 __ • _ .._ .._- ..•._--,--_ ...... ., .. ... ... " ._._----." .. .. .. ..... _ .... ..0._- _._----

f-- - ~- - - - .--- - .~-- - - -- '- -- -_. -_.__.- - - - -_. .._ .. ._-- _ ..--~_.- .._-

"" - _.~ "f'0;::: ..._ .._----- - .- -- - .,----- ---- _. - - - - - -- - - - 1- _. - -_. .- - - - ~-

-- --I-- - -_ .. - -- - - --- - - - - - - -_. - - - - - ._-

100

9080

1: 70•5PJ 60~ 50..:g 40I;:

C 30Q)

~ 20a.10

o10.0000


1.0000

=40%=30%=10%=20%

0.1000

Diameter In mm

0.0100 0.0010


"\- - - _. - -- _. _ . .-- _. .- - .- - - - --

- _. --- ~'-' ----- --------- "" .. .._. -~_.--- ------ . - -- _ .. _.- -- ----_ . . - .- -. - -_. ---,..----

"- - _. .- _. --- --- .. - - -- -I'- ._-_. -_. _..- -~~

---- -- - -- - ---- ----- ._--------

- - . - - --- - - - . - - - ~ -- - ..- - - --

- - - .- - -- - .- - - - -- -_. - _. - - - -~

- - - 1--- _. --.. - - •.-- -- -<_. - . - - -- ----- .- - ._. - - -- -- - - 0 -- - --

"- - - _. .- -- - - - -- - - - ",' - -"'--- :::0<>-- - - - 1- _.- - -- - _. - - - -- - - - - 1- - - 1--- .. - - --

- - . 1-- -- --- - - . .- -f-- - -- - -f--- - - --

~, .

10090

~ 80Cl'; 70>- 60..Q

t 50.s 40-i 30~ 20CL 10

o10.0000


1.0000

= 10%=55%= 17%= 15%

0.1000

Diameter in mm

139

0.0100 0.0010

.':-;l,.

Grain Size Distribution CurveBH- 07, D - 7.24 m

"'<:-. _ .. ._- .v", ----- .. - ...- --,. ----- - -..- ---_ .. - --- _ .._- ---'- - - -- - --- ....- - - - "- ---

"-- -- - - -- - -- - - --

- - - - - - -- - -- - - - --~ - - -- ---- - - -- - - -

- - _. -- ____ 0- - --- -- - - - -- --- ---_. - -- -- -_. _. - - -- - - - - - ,- -- - --- - -_. - - - -- - -- - -- - -r-..

~- - - - - -

- - - e----- - -- -- - - - -f- - - - - - ~ - - "----- -- - - - -- - - - -.- -- ---- - -- - --- - -- - -- - - - >-== - .- -

"(

- -- -- -- ---~- - -- - --- ' __ 'M_" - --- -- --- ._- _. -- -- ---- - - - - --- ---- - -- - - --

-.s::.0)-;~•..CDcI;::-c~CDQ..

100

908070

6050

40

302010

o10.00000 1.00000 0.10000 0.01000

Diameter in mm

0.00100 0.00010 0.00001


=3%=42%=20%=35%

Grain Size Distribution CurveBH- 08, D - 8.76 m

- --- - - _. - -- - -.•...

~ - - -- ...- - - - - - - -- -- _. _.

- --- - - - - - - - ~ - - '- - -- .- - - - - --- - - --- -

- .-- -- ._--- -- -_. -- ,---_. - -- - - -- -_.- ._._- ._. - _. --- _. -- ---

- - -- - - - -- -- - - - -- - \ - - - - -- - - _. - - _.

- - - - - ~-- - -- -

-~- - - - - -- - - -- - I------

- - - _._--- -- -- ----f-- - --- __0_- .- - --- ._-- ------ - -- ---- -- _. ---

_. - -1- -- - --- - -- - - - - - - - - - .-~. i'O'F-- _. -- --I----

- -- -- - --- - - -- -- - _. ,- - _. - --j- -- - _. -- -_ ..- - - - _ .. ::<\"0--

100

90807060504030

2010o

10.00000 1.00000 0.10000 0.01000 0.00100 0.00010 0.00001


=1%=34%=27%=38%

Diameter in mm

140 f

Grain Size Distribution CurveBH- 09, D- 3.05 m

'Q",

[j-- - - ._-- --'--". - - _. - -- - --- --- - - - - - -- --- - - . -- -- ._-- --... .._. --- . ._-_._ .... _.- - - --- - - - --- - -- - -- -----

- - . - -- -- - - - - - - -- - - -

.- - -. f- --- - .- - - . -_..- -- ---- - - -- - --- - - _. - - ---- - - -- - -- - --- - - - - _. '- - -- --_.- --- - -- - -- -_. - - - - - -- I- -_. --~- - - ---- - - - - - -- - - -- -- - -- - --

I':- - - ,-- -- -

- - -- ~~--- --- .- - .-.- - -- - -- - - _.

_. - - -- - -- ---- - -- - - - - - _ . .- _. -- -- - .... .._~... ._.-v-

100

908070

6050

4030

2010o10.0000 1.0000 0.1000 0.0100 0.0010 0.0001


=50%=35%=7%=8%

Diameter in mm

Grain Size Distribution CurveBH-09, 0-6.10 m

"" ~.- - - _.- - - -- - - -- - .•- -_. - - _. - - -- -- 1- -'I'~- I- - - -- - - -I---- - - - - --- _. - - -

- .•.- -- - - -- ---- - - - -- - ~ - . - -_.-- . - -- - -- - - - .- .- - -

- - _.- ._. .._-. -- -- -".- ---- - - - -- -- .._-- .- -- 0 __ - 0 __ • - - - -- --- --- - _ .. -- ----- ._- -_. -- - - - - - - -- -- _.- --- - - ..- - ---- - - - -_. _. _. ----:-.

~- - - - -f-- -- - - - - - - - - - c-

- .---- -- - . --- .0_- .__ . - - - .-- --- - - - - ~ -- - ._- -- - -- - - - -- .- .- -~... -_. _. .-. ._- --_. - -- - ._-- ---- - - .- - - ---- .- .. ""'(

_. - .- -- ---':-

.- - ---~.------- . _ . - ._- - -- ---_. - .- - .- ._-.-- --_._. .. ..- .- ._- -- -.-~- '""< ----

100

908070

6050

40

302010

o10.0000


1.0000

= 10%= 40010=20%=30%

0.1000 0.0100

Diameter in mm

141

0.0010 0.0001 0.0000

I~,

"'" ~- - - -- -_. - - - - --- - - - .- - - --- - .- - - - -- - - -- ..._-- ,- - - - - -- _.- - _. - - - - - .-

- - - - - - ._. - - - ,'""- -1-- - - - -\ -- -- - - - -- - - - ~ - -

.. - •. ._- ._- --- --~- , . .- ._. -- ._... ---- - - _ . ._- --- -~-_. . , .-1- --- ---- - -- -- _.

- - - - - -- - - - - - - - - 'b,. ~ - - c- - -_. -- - .- ----- -- -- .- ---- - - -- .-- - -_. --- .- - -- - ~ . - - - -_.

"'1- ::'9-- - _. ..- ---- --_. -- -- - _. - -- - .- _•._ .. ------- - --- -_._._- . - .. ._- ---,.

10090

E 80Cl

.~ 70>. 60.CI

:u 50~ 40-c 30~Ql 20Q. 10

o10.0000 1.0000 0.1000 0.0100 0.0010 0.0001


= 18%=42%=20%.=20%

Diameter in mm

Grain Size Distribution CurveBH- 09, 0- 22.86 m

i"<,~- - - - ~

-- .. - - - -_. _ ..- - - - - -- - - - 1- ~ -- -- - - - -- - - _. -

- ._-- - -- .._-- .- - _. -, - ---_. -- _ . .. --- -, .__ .. .- -- - ._- . . ---' -- .__ ..

•• ---- - -- -_. _.- .. -- - ..- _. -- -- - -- - - -- .- .. - "-- -'-, - _. -1- -

-- .. - - - ---- -- - .. - - --._- - ... --- -- -- , -- - .. - ~~

. - - -- - _ .

" .. _. ..- -_. ----_. ".. - _. .- ---" _.'--- , .- ... ..- -- ---- •.- - . .. - -_. ----- -- .. - --- -- -----

.- --, - - -- . - ._. - -_. -- .. ,,-- --- - -_ .. -- - ---- ..- --- .. -- .•. ... "00-<<>-- -- 1- --- -- - - -- - - -- - - - - - - - -- - -. - - .- - -_..e----

-- -- - - - .. .

100

90•• 80.s::.Q1 70>. 60.alis 50r:::

-,- :: 40r:::

~ 30Q. 20

10

o10.0000 1.0000 0.1000 0_0100 0.0010 0.0001


=1%=34%=25%=40%

Diameter in mm

142


-~- - --.. -- ------ .. - - ._- --_. - -~- .- ----- - -- - - -- - --_. - - - -- -- ---

_. - - - .- --

- - - - .. - - -_.i\ ._- - ,

- --+- - ._- - .. - _. - 1- - - _. - -- - ~ - --- - --- - - --- -- - .---- - - - - ~ -- -- - - -- -- -_.- ~_.-...•.

:::.- .-- --.,._. ------ -- - - -- - -"-- - -- -- - .- -~ •....•-""'--- .- - -- ---- -•..... -....,-- .. -- ._- ---- -- _. - .- -- ---- - ..._. - .. - _.~.--_. ._--...- - ... .-- _. _ .. _.- -_ ..~-_. - - - -- .._---

- - - -- --- ----- - .. - -- _.- --- - - - .. -_. - .-.._-- - _. - ..~.-'-' -....-_. --- "._- ---- ~----- - ..- - ._._- ---- - - - - _. ---- - - .- ._- -_. --- -- -_. - _.- -- --- ---- .. .- - - _. _. ---

..s:.Cl.~~..QIC11=

IQIa.

100

908070

605040

302010

o10.0000 1.0000 0.1000 0.0100 0.0010 0.0001


= 18%=32%= 15%=35%

Diameter in mm

Grain Size Distribution CurveBH -11, UD -1, 2.67 m

.,.. -0-- ):; -

......•- -- - - - -

~,

.- -- ._- -_. ._-_.- - _ .. ...- --- .. .-- -- -- - - - - -- -~ - - -- -~ .'-

- -- -- - -- - ._- ----- - - --- .-- ----- - - . - - -- _.- ..- '- - - _ . .- -- -'---...•.r-....... _. -_.. .__ .- - -- ... - ._--_. - - - -- --- -- -- - _. - --- -_. - .. - -_ .~ - .. .-.. -- -----

r-. 0..__. - ---- .- _ . .... -- ._.-' - _. --_.- -- .. _. •._•. .._-- ... .- - -_..... .. _. ---.

.. _.-- - - . .- - - -- - - ._-_.- -- - ... _. ---- - .. -- _. --- .. - .- - .----

- - _. --- - - - - - 1-. -. - _. - -- - - - -- - - -- - -- -1- --

- - - - - - -- -

100

90

80.. 70s:.Cl

1 60

~ 50..QI

40cIt:..

30c~.. 20QIa.

10

o10.0000 1.0000 0.1000 0.0100

Diameter in mm

0.0010 0.0001 0.0000


=1%= 11%= 18%=70%

143

- - ._-- . - -- -- -, . ._. - .. .. \1-.__ . .- .. ... _ .. -_ . - - _ .-- ---- - -- --_.

~ -

. -_. - _.- - - .. ~ - - - - - - - - -'\.. - -_ .. -_ .._. .. - _ . .- ..- .. .' .. -_. -- - .-_ ..-- . . - .-. ------ . - f...' -- ---

.. ... _.. .- ___ 0 • .. .•. _.' ._._--_ . - ... _. _ .. '--- ... .. ...... ----- - .•.- ._- "-_.-. - ... ._. _._--I'....

~. - -- .- ---- .- - .- ---<. -. - - - - - - ._. -- -._. ... _. -- -- -_.

- - -- -- - - -- -- - -- ._.-- . - ~. -- -- .. _ ..- _ .

- - _. - - . - .-- - - -- - ._. - - - 1- -r<

- .. ..-- - - -- -~. .- - .. -- --- - I--- - - - -~ - -

''f

100

90

80-.c~ 70I 60>-J:lt 50c

11= 40-cCII 30u..CIIQ. 20

10

Grain Size Distribution CurveBH- 11, UD - 3, D = 724 m

,,1+-,

o10.0000 1.0000 0.1000 0.0100

Diameter In mm

0.0010 0.0001 0.0000


=2%=48%:= 20%=30%

Grain Size Distribution CurveBH-11, 0 = 10.67 m

~- - - --,.- - -- - - - _. - ".. .._ . .- - ".-_ .... .. - ..- .__ . .._--' ' .. .- ... ~ .. ... ..... ..- .•... .. .• .• -, .. ..- -,-::--:

.. .. ... _._ .. -.. -- -- .. ._-- --_.- - ... ..._. .---~

.. -- ...... - _ .. _ ._._-_ .. - .. ..- .__ . - .-..._---

... . -" -- --_._-_ .. _. - .- --_ . ._- - - - ..- - ---- - - - _. -- ._. ._------ - - - _.. - ._. -_.-.

- -- - ~._- - - ... - --- .- -- - ..-_.-- ----- . .. - ---- - - .. - _ .-"'-

~- - _. .. -' -- -- - .. . .. --- ---.- - - -- '- -- ----_. - - _. - .. -- -- i-- --

- - '- _. - - ~ - - --_ ... - -- _ ..-- - .. - ._. -- - - I--

- -- _.- - --1- - - - -

- - i- I- - -- .

-.c01

1~..CIICll=-C~Q.

100

90

80

70

60

50

40

30

20

10

o10.0000 1.0000 0.1000

Diameter in mm

0.0100 0.0010 0.0001


=2%=48%= 18%=32%

144

Grain Size Dismbution CurveBH-11, D = 13.72 m

"""0

-- --- ---- ---- --- -- - - --- - - --- ---- - -- ..... - -- - - - -- -- ---- - -

-~

-

- - -- - - - - -- -- - -"- - - - - - - --

- - -- --- -- --- ~._.. ---, -- --- -- ---rs - -- -- ._-- - -- - - --- - - - -----

--- --- --- -- _ .•. -- .__ . - -- ,-- ---- -- --- -- -- - - --- ......._- -- -- -- .---_.

-- --- -_.- _._-_ .. - -- --- -- - ._-_. -- -- _ ..- - - .'~'-'-- -- --- -- -_.-. -- - --- ---_. -_._- - --- - ._.- ----

- - -- --- ---- ">......- - - - -- - -- - - - - -- - - - - - - -- -

- -- -- - -- _.- ..- -- - --- --- ------- -- - - --- - - -- -- -- ~ -- -- --- -- -- - -- -- --

- - --I- -- --- - - - - --- - --- -- I--- -- -- - --- - -- -i"Q

-.cC).~~•..Q)cq::-c~Q)Q.

100

908070

605040302010

o10.0000 1.0000 0.1000 0.0100

Diameter in mm

0.0010 . 0.0001 0.0000


=2%=60%= 18%=20%

Grain Size Distribution CurveBH-11 , 0 = 21.33 m

"'Woo

- - - ---- - -- - - - - - - -- - - -- - --\

- - - -- -- .__ .__ . -- ---- ----- -- ~--- -- - -- - - - --- - - - -- - -- -_ ..--

-- -- -- -- ...... --,-_ .... -. -- -_ .. -_ .... "._--_ ..-. -- -- --- --- '\ .._- -_._- -- .. - ...- ..__ . - .... --- ."-'-"-'.

- -- -- _. _._. _.-- - -- - --- --- ----- - - - -- --- ---:s -- - -- -- - ---~.- - -- - -- ._- -----

--- - --- - --- ----- - - --- - -- - --- --- - - -- -- - - -- - --

- _.- - - -- -- - - _. - - -_. - -- --- - -- - - ---- -- -- - - ------

'" ~_. -- -- -- --- --- - _ ..1- -- -- - - -- - --- --- - -- - ---- - -- -- -- -----~ ,

-- - - --- - ---- - -

- - 1-- -

100

90

80-s:. 7001~~ 60~•.. 50CDc"" 40-~ 30CDQ. 20

10

o10.()(XX) 0.1000 0.0100 0.0010 0.0001

.\.


Diameter In mm

=3%= 5<)010=18%=20%

145

Grain Size Distribution CurwBH-12, UD-1, D -2.67 m

-v-

- _. ,- - - -- - -- -~ l-.o. - - - - - -

- - - -- - - - -- -- - - --I-- -" --- -- - .--- -- --- --- -

"- -- - - -- - - - -- - - - - - --~

- - - -i-- ---

- --- - - .._- - -- -- -- --- - - -- - -- -- -- - --- - - - -~~

~-- -- - --- _ .._--- - --_. ----- - --- -- -_ .. -_..- -- - -- -- --- -- - - ---- -

--- - -- - - - - - - -- --- - -- - -- --- I-- - - - -\ - -

- -- - - - -

- -- - - -- - - -- -- -- - - I------- - - - - - - - - -

- - .-1-- -- - -1-- -- - -- - - - - - - --_. - - ---- - - -- - I-------

-,.. ..

100

90

80..s:.70Cl

1 60>.J:I.. 50CDClI: 40..c8 30..CDa..

20

10

o10.0000 1.0000 0.1000 0.0100

Diameter in mm0.0010 0.0001 0.0000


=2%=15%=21%=62%

146

APPENDIX-C(Unconfined Compressive Strength Test Results)

147

~,lr\

South Central Road, KhulnaBorehole No. 01, Depth 2.67 m

~ -0- ~Clu = 70.00w;-O- """'""--/

,..,...-",=33.56%

--0

/ '\ Gs=2.72"Yd=13.45 Wnil

/ "y_ =17.97 Wnil5=93.01 %

/ E, =6.0%

r N=3

n

90-Me 80"""-

~ 70= 60=',;;~ 50~~ 40.~ 30~ 20c.e

.~. = 10Uoo 2 3 5 6

Strain (%)

8 9 11 12 14

South Central Road, KhulnaBB 02, Depth = 2.67 and 5.71m

qu=21.95kl'lVm2

w =77.07 %Gs=2.62e=1.68 .--0- --.r ~"Yd =11.51 kl'lVm3 ~ ~ N~u=65.00 kNlm2

'Yb=15.72kl'lVm3 ~ \" (J)=39.88%

5=99.92% \ 05=2.61

Ef =9 % 'Yd=12.78 kNlm3

N=1 'Yb=17.87kNlm3", 5=100.00%

I ~Ef =9.0%N=2

I / ~

~

80-Me 70

Z60e.....•..' =c::r 50,;;

~ 40~~4.l

30.r::."rl20

"'"c.e= 10U

o0.0 1.5 3.0 4.5 6.0 7.5 9.0 10.5 12.0 13.5 15.0 16.5

Strain (%)

148

-o-UD-01, 2.67 m -<>-UD-03, 5.71 m

I-

a .

Rupsba Feri Ghat, KhulnaBB= 04, Deptb=4.19 m

I I I I./ \\. ... --/~ !,:.---' I~""J ~ f-......Ilu =92.0 kN'ni!

/ w =33.0% ~'Gs=2.84 ~

/'Vd =14.33 kN'rn''Vb =18.20 kN'rn'5=81.42 %

Je, =7.0%N=2

60-""s 50.•...Ze:I 40C"

,;;'"e 30•..

rLl~.~

20'"'"e=-s 10Q

U

oo 2 3 4 5 6 7 8 9 10 11 12 13 14

Strain (%) -0- UD-04, 4.19 m

..."..

KhuIna Medical CollegeBB =OS,Depth =5.49 m

40

35-""..e 30

~=

~ ~--0-- -v

:I 25C"

/",,- llu =30.0 kN'fTi2

,;; w=52.1%'" 20e Gs=2.60- / Yd=7.95 kN'rn'rLl~ 15

/Yb=14.32 kN'rn'.~ 5=95.19%

""'" ef = 10.0%e 10

~C. 1IF1

S5Q

u VII:0

i0 I 2 3 5 6 8 9 11 12 14 15

: Strain (%)I I ~UD-3, 5.49 Ii

149 \.

.f,t,

I Kbulna Medical CollegeI DR= 06, Depth =7.47 mi

120

III I105.r-

IIIII 90

III I~f-/ I,g.75

~ il: I~ \"'Jllu - 93.0 kN'm7

J: 60 .1 w=43.0%fI.l

:1:~ Gs=2.68~ ",..,... "Yd=11.97 kN'rri'~

45.~ill / "Yvoel=17.13kWrri'~

100 5=96.74%g. 30s I!I/I 9 =11.0 %a15 ill N=3

A0I

0.0I

1.5 3.0 4.5 6.0 7.5 9.0 10.5 12.0 13.5

I Strain(%)

I ~UD-02, 7.47 m I,

II

:11

Iii

Khulna Polytechnic Institute

150BH=08, Depth = 8.76 and 10.28 m

III I I I I135

Iiiqu = 89.0 kNlm2

120 ",=50.3%.-..ill

Gs=2.70..•.e 105 "Yd=13.54kNlm3

~ 'Yb=17.52 kNlm3 I90 5=84.72%" _\ I ~c:1' Ef = 12.0 % VY T "Q.... ~"'---. 75•• N=5•• ~ ~ -~ qu = 83.0 kN/m2 t--e- 6000 I~~

",=35.40%~ Gs=2.84.~ 45 "Yd=10.53 kN/m3.. /~'..e

30 'Yb=15.78 kNlm3

c.a15 I!i'/ '/ 5=86,53%

Q Ef = 11.0 %U

o~N=4

I

0.0.1 1.5 3.0 4.5 6.0 7.5 9.0 10.5 12.0 13.5 15.0 16.5

Strain (010) 1-0-UO-Q1, 8.76 m -0- UD-02, 10.28 m I1

II

"I

.1

I

150

I II .......•

1.-/vo-U\

q. = 41.0 kNlm'

VI w =41.80%

~'Yd = 11.51 kNlm''Yb =16.66 kNlm'

JV 5=95.6%

E, = 15.0%

V N=3

I

Goalkhali Dumb Schoo~ KhulnaBH= 09, Dept1F=7.24 m

o70

"C"

~40e-rI}~ 30.ii=....f 20c.aQ

.~ U 10

o0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0

Stmin(%)

Physical Handicraft Training CentreBH=10, Depth =7.24 and 8.76 m

~ UD-01, 7.24 m

140-Me 120Ze 100"-'1" C"0-

W> 80W>

~.•..V2 60~.iI:W>W> 40~=-e 20=U

00 2

q. = 61 kNirri!w =40.8 %'Yd = 12.58 kNlJril'Yb = 17.73 kNlJril8=98.6%Ef = 15.0%N=3eo=1.13Gs=2.74

4 6 8 10 12 14 16

Clu= 119 kNlrri!",=38.4%'Yd =12.28 kNlJril'Vb =17.37 kNlJril8=92.0%Et =10.50%N=4Gs=2.75

18 20

1'-.

Strain(%)I ~UD-01,7.24 m ~UD-02, 8.76 m I

151

Sonadanga Thana, KhulnaBH=l1, Depth= 4.19m

50

••~30....•••f.•..

CI.l

.~ 20........fg.

e 10Q

U

o0.0 1.5 3.0 4.5

q" = 41.0 Wm1",=34.0%Gs=2.65e.=0.83'Y.=13.30 klIVld'Yb =18.60 Wid5=99.50%., = 9.0 %~1

6.0 7.5 9.0 10.5 12.0

Strain in (%)-<>-UD-02, 4.19 m

Sonadanga thanaBH=12, Deptb=2.67 and 4.19 m

100

.(16.515.0

q. = 7.0 klIVm200=52.9%Gs=2.65'Yd =10.65 klIVrn'l'Yb =16.29klIVrn'l8=97.65%E, = 15.0%N=1

13.512.010.5

-<>-U[).()1, 2.67 m -<>-U[).()3, 4.19 m

6.0 7.5 9.0

Strain(%)

4.5

q" =51.0 klIVm200=35.9 %Gs=2.65'Yd =12.98 klIVrn'l'Y•••t =17.64 klIVrn'l8=95.12%E, = 12.0%N=2

3.01.5

-~80ZC

••~60•••.•.G.l•....•..00G.l

.:: 40•••.•.G.l•...Cl..

~ 20U

o0.0

152

APPENDIX-D(Direct Shear Test Results)

153

Nonnal Stress vs Shear stressBorehole No-G1, Average Dep1tt=21.33 m

~

.//

/~

~~

.

,~.

403632I 28-en 24enCD..

20••en..= 16oS:(I) 12

8

4o

o 10 20 30

Normal stress (psi)

Shear Stress va Normal stressBorehole No-01,Average Depth=25.90m

40 50

~

~.......-

~v

//'"

/'"V

t"l/'

40

36

3228

=_!t24

~ 20'Iiili 16~ 12

8

4

oo 5 10 15 20 25 30 35 40 45 50

Normal stress (psi)

154

(\

403632

~2824

$i 20•.. 16IIIQ)m 12

84

Shear Stress vs Normal StressBorehole No-3, Average Depth=21.94 m

~

//'

~

..•..• ~

,../V

Normal stress (psi),,:a.,I~

oo 5 10 15 20 25 30 35 40 45 50

Shear Stress vs Normal StressBorehole No-3, Avrage Depth=27.43 m

5

40'

3632

l 28';;' 24

~ 201ii~ 16~ 12rn

8

4 ----

oo 10 15 20 25 30 35 40 45 50

Normal stress (psi)

155 /\

••

Shear Stress vs Normal StressBorehole-4, Average Depth=19.81 m

----l--1---....L.-o--V

V

~' ..~....'\

40

3632

28242016

12

8

4

oo 5 10 15 20 25 30

Normal stress (psi)

35 40 45 50

42

36::::r! 30III--..., i 24III.. 18m.c(/) 12

6

Shear Stress vs Normal StressBorehole No.06. Average Depth=19.81 m

oo 6 12 18 24 30 36 42 48 54

Normal stress (psI)

156 , -

--0

----- ~-

~....--

~

I

Shear Stress va Normal StressBorehOleN0-6, Average Depth=26.52 m~~

42

36

30C"CI).e: 24••CI)•.b 18CI)•..:I

12.c{/)

6

oo 6 12 18 24 30

Normal stress (psi)

36 42 48 54

Shear Stress vs Nonnal StressBorehole No-7, Average Depth=28.95 m

-

~~ .•..

----- ~~

~

I I I

42

36

l 30-CI) 24--w( CI)!- 18CI)•..= 12.c{/)

6

oo 6 12 18 24 30

Normal stres8 (psi)

157

36 42 48

APPENDIX-E(Consolidation Test Results)

158

0.123

0.125

0.128

0.130CIc:'6III 0.1330::

~ 0.135

0.138

0.140

lime vs Dial reading at FaraziparaSouth Cetral Road, BH-01, depth =2.67 mCasagrande Method, pressure =100 kPa

0.",

~r'-.i'"

~

""' ...•"'<>-....... -0...

-I'"<

0.1430.1 1.0 10.0 100.0

Time (minute)1000.0 10000.0.

1\\\\

~~ ...........••

/'-0... -~ -.. ..

0.0 0.50.114

0.116

0.119

0.121

.5 0.1232ii 0.125~ 0.128"'iiio 0.130

0.132

0.134

0.137

0.139

South Central Road, BH-01 , Depth =2.67mTaylor's Method, Pressure=100 kPa

Sq. root oft (min)

1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0

159

Time \ersus consolidation at Farazipara,South central Road. BH-Q1, Depth=4.19mcasaarande Method. Pressure = 100kPa

v.••••• 1"<

, ...

~ ~I-- ro...

"'-c

~ •.•..........r-cl .

.•...•..

0.1 1.0 10.0 100.0 1000.0 10000.0

Time (mnute)

6.05.55.0

South Cetral Road, Taylor's MethodBH-1, Depth=4.19 m, Pressue = 100 kPa

Sq. root of t (min)

1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.50.5I I : I I I : , , I '

- ---- i--- .. -1-- - -- -- \-------\-- ----1-------- i ------ ---i-- --- ---+- .- -..-- \--- -.-----1--- -- \- ------

-~j_-_~-j __--J ~---~--1- ---- --- !~_-_::_J:- -j-:-! --~---I-:-~-~J-----~\~~:~-=, \' , I I ii' , , i

-I--~-----:---------!----j--------i---------I------t----L-----!----)-------~-------,.1 .\ ----LL-----..I- .. --,-------.; ! .-.. ! ---.. ----,----------- 1,------- ~I \----1

1- ----- \1-------.1-- ! !_-----l-----;----i----

.... - --1- -- --.... ---' -- L. --- ---f--- ..-- .. i ------- ----..-----.

_______\ - __ \ "_'__' __ \ ---1-- I I _! ... JI ! I __ I ----\-------\----L------i---~~~~---\.-~---.--•••-~•.l~~--••-]--=~~-~.\_. 1 .._.._ \.---- ._l. -.-\ ------I I I ! ! . \ !

0.00.1540.158

0.1630.167

0.1710)c 0.175:g~0.179(ij 0.183i5 0.187

0.192

0.196

0.200

.~

160

South Central Road, BH-02,UD-1Depth =2.67m, Pressure=100 kPa

.•.. ~.•J;..,-

0.133

0.136

OJ.S 0.139'Ceu~"'iii 0.143(5

0.146

0.1490.1 1.0 10.0 100.0

Time (rrinute)

1000.0

i I! iI!! !

10000.0

1\

\\'\

,\

\.••.•....•.•

~"'"""

""<> -- .

South central Road, BH-Q2,UD-1Depth =2.67m, Pressure=100 kPa

Sq. root of t (min)

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.00.130

0.132

0.133

c:: 0.135

.~ 0.136

~ 0.138

~ 0.139

o 0.141

0.142

0.144

0.145

161

South Central Road, BH-02,Ud-2 Depth =2.67mCasagrande Method, Pressure=1oo kPa.

o,r-.

~'"f-.

1'0.. :---.."0.....-

"U.,:--."(

'-

0.153

0.156

0.160

0.163

g' 0.166'6~ 0.170

~ 0.173

0.177

0.180

0.183

0.187

0.1 1.0 10.0 100.0 1000.0 10000.0

o0.153

0.156

0.158

.5 0.161

~ 0.163

:g 0.166~a; 0.169

i5 0.171

0.174

0.176

0.179

1 2

lime (rrinute)

Time vs dial reading at Farazipara,South Central Road, BH-Q2,Ud-2,Depth =4.19m. Pressure=1oo kPa.

Sq. root of t (min) .

3 4 5 6 7 8

162

9 10 11

.

0- •••

"r--. "--

""" i'.,

..•.•-ro- i'"'k

-0

BH-05,Ud-1Depth = 2.67 mPressure=1oo kPa{

0.130

0.133

0.136

0.139Clc::

"6 0.1421IlQ)

0:: 0.145"ii

o 0.148

0.151

0.154

0.1570.1 1.0 10.0 100.0 1000.0 10000.0

Time (minute)

BH-05,Ud-1, Depth = 2.67 m,Pressure= 100 kPa

Sq. root oft (min) .

0.0 0.8 1.5 2.3 3.0 3.8 4.5 5.3 6.0 6.8 7.50.131

0.134 -

0.136

0.139~!1I .!:

C) 0.141c~ 0.144~(ij 0.146~

0.149

0.151

0.154

0.156

163

I I iI I !II

(). ~~ l I IIi

i .....,

"'f'II

!1

! I .

I I I I

I i II ,

I I~ I

1iI

!

Ii 1", •.... i

\ I i1

II !' I.~ I

\ -:-0I I 1

1I I

I I I !

0.081

0.086

0.091

g' 0.096~ 0.1010::c5 0.106

0.111

0.116

0.1210.1 1.0

BH-05,Ud-2 Depth = 4.19 mPressure=100 kPa

10.0 100.0

Time (rrinute)

Taylor's Method, BH-05,Ud-2 ,Depth = 4.19 m, Pressure=100 kPa

1000.0

:'.;,

10000.0

.5

g; 0.096 --'gQ)0:::iiii5 0.101

0.00.081

0.086 -

0.091

0.106

1.0 2.0 3.0Sq. root of t (nin)

4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0

0.111 ._- --

164

Casagrande method, BH-07,Ud-1Depth = 7.24 m, Pressure=100 kPa

I I !I

, i

1Qr--- II I II l I;

~~ I ]I

!!

" I I iII i I

!

I ~iI~ !

I "",! ~L i

I! i!

I I "' ~ II

iII I l I

III I i! ~

•..

0.1090.111

0.113C).5 0.115m 0.117a::16 0.119o 0.121

0.123

0.1250.1 1.0 . 10.0 100.0

lime (minute)1000.0 10000.0

..- _I------- ..._ .... _ ...- ._..._----- ._------- ~~--------- '--.._--_. __ . ------- -_.__ ._- ._--_.- _._---- ------

.. ---- ---- -.---- ---- --- --_._ .._. ------ .-_.-.__ . .._---_. ---_.--_ . .__ ....._- ----_._--_.

'-' - -- -- ~- -- -_.

~~

~- ---- --

.

~ ----<l-

,- --

Taylor'smethod,BH-07,Ud-1Depth= 7.24 m, , Pressure=100 kPa

Sq. root of t (min)

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0 12.00.0975

0.1000

0.1025

0.1050.5C) 0.1075

".., c::ecu 0.1100Q)0::a; 0.1125is

0.1150

0.1175

0.1200

0.1225

165

,"'{

Casagrande method, BH-11, Ud-2Depth = 4.19 m, Pressure=100 kPa

,.

I\ j

.. IVI

~~

'"~~

....••~r- I

~

1

.~ 0.075

0.080c~•. 0.084ac.-i 0.089fCi 0.093is

0.098

0.1020.0 '0.1 1.0

Time

10.0 100.0 1000.0 10000.0

Taylor's method, Sonadanga BH"'11,Ud-2Depth = 4.19 m, Pressure=100 kPa

0.0 .0.8 1.5 2.3 3.0 3.8 4.5 5.3 6;0 6.8 7.50.070

0.075

.5~ 0.080

1 0.085]Q

0.090

0.095Time

166

•'.

....•.. -_ .....'-

APPENDIX,- F(Calculation of Different Types of Foundation Systelns)

167

(a)Option of individual column footing on existing soil

Plan and elevation of footing have been typical for six-storey apartment

15'-0' 15'-0'

---f1\---L\:17 II I I~ I I A I

I I Ii----t----rPlan of frame structure

Unfactored load at interior column =270 kip

Assumed Footing Size = 10'-0" x 10'-0"

Stress below the pad footing = 2.70 ksf

Calculated settlement

- -"',,".'" rRIIn

.-RI. u.m

E -G90 1- --,• <D clay eIIt0<00.2S0 ...0.95.. --- ea-O,l1037

!, o cl8yllftce-1.as.e-.022__ eom 0:lD3.11

:;) @ silly cI8y0<00.38, co' 0.0018_.58

:;) <9 silly cI8yCC"O.54,c.' 0.0019...0.79

@) eIIty••• d

Elevation of footing and soil layers

~s = 0.49 for saturated soil

Es (wt. avg.) = 1602 ksf

«=4Df=3.28 feet

B = 10 feet

L = 10 feet

-Layer Elastic settlement Primary consolidation Secondary consolidation(inch) settlement (inch) settlement (inch)

Layer-l 7.40 0.105

Layer-2 1.76 0.019

Layer-30.180 0.45 0.60

Layer-4 0.64 ".:~ 0.023

Sum 0.52 10.25 0.75

Total 11.12settlement

168

~,l '~

- . "i-(~ ;$........•.. '"- ~..-_.\..~,.:' (b)Option of mat foundation on existing soil

~\'~I

~ ..•••••

eo,..;


Fnfing sand

CD clay silt Cc=O.26e.=O.95

~•••_...., Ca=O.OO37

@ clay silt Cc=1.95, Ca=O.022~ ••• r.m""'" e0=3.11@ silty clay Cc=O.38, ca = 0.0018

e.=1.58

@ silty clay Cc=O.54, ca = 0.0019e.=O.78

@ siltysand

Elevation of mat and soil layers

Assumed soil pressuredistributed at 30° angle.

Layer Elastic settlement Primary consolidation Secondary consolidation(inch) settlement (inch) settlement (inch)

Layer-1 2.03 0.029

Layer-2 0.64 0.0072

Layer-30.52 0.18 0.011

Layer-4 0.28 0.016

Sum 0.52 3.13 0.06


169

@ slltysand

(c) Option of mat foundation with Khoa Matten

eo-,;

EoNEoN

-;11-PU+1'''''''

,Alfingoand

RLIO'-Il"\ .. It.:. -GB

-....... . ". . ' .. ...CD clay sift Cc=0.26

_0.95Imn~BK.a:Z Ca=0.0037

@ clay silt Cc=1.95,Ca=0.022tI!o:wnfl'llm&+.01 _3.11

@ silty clay Cc=O.38,Qx= 0.0018_1.58

@ silty clay Cc=0.54, Qx= 0.0019_0.78

Assumed soilpressure distributedat 45° angle.

-(,

Elevation of mat and compacted Khoa matters


Layer Elastic settlement Primary consolidation Secondary consolidation(inch) settlement (inch) settlement (inch)

Layer.} 1.89 0.032

Layer-2 0.29 0.003

Layer.3 0.52 0.09 0.0004

Layer-4 0.13 0.0005

Sum .0.52 2.75 0.036


170

taken tom BH-02

(d) Option of Rammed Aggregate Pier (RAP)

clay silt Cc=0.26eo=0.95Ca=0.0037

o clay silt Cc=1.95, Ca=O.022 IIaken tram BH.Ol eo=3.11@ silty clay Cc=0.38, Ca = 0.00181

eo=1.58

(3) silty clay Cc=0.54, Ca = 0.0019eo=0.78

Elevation of Rammed Aggregate Pier(RAP) and soil layers

Assumed data:

Footing size = 8' -0" x 8' -0"

Stiffness ratio of Geopier, Rs = 8

No. ofGeopier = 8

Dia of Pier = 24"

Ratio of Geopier area to footing area =0.39

Geopier stiffness modulus = 108 kfft3

Calculated settlement:

Settlement of the upper zone = 1.03"

171

t

ii

r

<3> Cu=10 kPa

@ Cu=71 kPa

@ Cu=68kPa

Section of Pre loading with sand drain

I -

\~\Vt:~f:)Preloading with sand drain

r>-F", 'r,"

Assumed data:Proposed structural loading = 2.75 ksf

To attain 91 per cent primary consolidation within 6 months, it is required 8

feet soil embankment loading with 16 inch square sand drain at spaced 4' -6;'

interval.

S = 4',,6"

Degree of consolidation, UV,r = 0.91

Vertical degree of consolidation, Uv=O.1183

Time factor, Tv = 0.011

Radial degree of consolidation, Ur = 0.898

Rd = 8", N=4, Ur= 0.880

Results:

One way drainage, No smear zone

Loading is instantaneous

Dia of Sand drain = 16"

Square pattern of Sand drain

Cv =6.0 rn2/yr.

Calculated values:

..-----.

•II,."..

\

'-,......, .---- ~

f

lI •..'".~I!

i!(

~ ..

IIIb.p

172

~a ',y ~.•. ( - , 0 :/.1//)9. ~ ' sj

Documents