geo –investigation report · field work 1. selection of bore – holes :- 1) 3,nos number of bore...
TRANSCRIPT
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CERTIFICATE
This is to certify that the samples are collected from the proposed site OPGC PROPOSED
FOR SOIL INVESTIGATION WORK FOR CONSTRUCTION OF CHP AREA AT MINES
END. The laboratory tests have been performed under the supervision of qualified personal,
as per the Indian standards and that this report is prepared on the basis of these tests
results and expert experience.
FOR: CADD CONSULTING ENGINEERS PVT. LTD
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INTRODUCTION
It is intended to investigate the sub soil strata at the proposed site of OPGC PROPOSED FOR
SOIL INVESTIGATION WORK FOR CONSTRUCTION OF CHP AREA AT MINES END
OBJECT
The object of the Geo – technical investigation is to:-
Optimize the foundation system, assuring the safe bearing capacity of the soil.
Determination of type, size and depth of foundation.
Analyzing the soil properties.
Suggesting an economically viable of foundation system to be adopted for the proposed
structures.
SCOPE OF WORK It consists of the following:-
Visual reconnaissance of the site.
Field and laboratory investigation.
Engineering judgment based on the current practice.
LIMITATIONS OF INVESTIGATION
The scope of Geo- technical Sub soil investigation is confined within the framework of
agreement and Technical specification with the client. However all the field and laboratory
experiments will be carried out as per the relevant Indian standard code of practice?
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THE DETAILED GEO-TECHNICAL INVESTIGATION WORK TO BE CARRIED OUT
CONSISTS OF TWO PARTS.
1. FIELD INVESTIGATION
Location of bore holes.
Boring /drilling up to specified depth below G.L.
Conducting standard penetration test.
Collection UDS samples.
Collecting DS samples.
Determining the depth of water table.
Study of site condition and surroundings.
Taking observation of surrounding structure.
Transportation of all soil samples to laboratory.
2. LABORATORY INVESTIGATION :-
Grain size analysis.
Determination of moisture content.
Unconfined compressive strength.
Determination of Bulk density.
Determination of dry density.
Determination of Void ratio.
Determination of liquid limit.
Determination of plastic limit & plastic index.
Determination of specific gravity.
Determination of shear parameters & settlement calculation.
Determination of DFS test.
LOCATION The proposed site of construction OF OPGC PROPOSED FOR SOIL INVESTIGATION WORK
FOR CONSTRUCTION OF CHP AREA AT MINES END 3
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FIELD WORK
1. SELECTION OF BORE – HOLES :-
1) 3,Nos number of bore hole was selected by the Engineer – In – Charge in order to
obtain comprehensive sub-soil data for this site up to specified depth in BH NO-8 TO
10 , below G.L. For detailed laboratory investigation SPT is conducted in suitable
intervals and Disturbed /undisturbed soil samples from the above bore hole were
collected at different levels from as per the instruction of the client with observation of
the ground water level during investigation.
2. BORING :-
2) The sub-soil exploration work at the proposed site was carried out using 150mm
diameter rotary calyx rig boring equipments.
3. STANDARD PENETRATION TESTS :-
3) Standard penetration tests we are conducted in different levels in a continuous manner
using a spilt – spoon sampler. The SPT sampler was lower inside the bore hole after
drilling the required level and is driven by a 65 kg. Hammer with a free fall of 750mm.
In three stages 150mm each and the numbers of blows for each 150mm penetration
was recorded. The details of location and SPT value [N] is shown in bore log data.
4. GROUND WATER TABLE :- 4) During the field work ground water level was observation in bore hole and the level of
ground water table are shown in bore log data.
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LABORATORY TESTS The laboratory – tests were conducted on selected SPT / disturbed / undisturbed soil samples collected from the bore holes drilled at the proposed site. The tests include grain size analysis, natural moisture content, D.F.S specific Gravity, liquid limit, plastic limit, plasticity index test and shear test. Particles size distribution tests on representative soil sample were also carried out. The laboratory test confirming to the requirement of I.S and specification were conducted on the soil, sample. The results of all these tests are given in test result sheet separately.
GRAIN SIZE ANALYSIS: The grain size analysis of different soil samples were done as per the requirement of IS: 2720(Pt- IV) 1975 – method of test for soil, Grain size analysis. The details of the test results are shown test result sheet separately in tabular as well as graphically. The result of grain size analysis is used to classify the soil in various depths of bore holes.
NATURAL MOISTURE CONTENT: The natural moisture content were determined as per IS: 2720(Pt –II) – 1973 – Method of test for soil, determination of water content.
DETERMINATION OF BULK DENSITY: The Bulk densities were determined in the laboratory from the UDS samples at different levels and the result are shown separately in tabular form.
DETERMINATION OF DRY DENSITY: The dry density of the UDS/DS samples was determined at the known moisture content and bulk density.
DETERMINATION OF SPECIFIC GRAVITY: The specific gravity of the UDS/DS sample was determined at different levels and the results are shown separately.
DETERMINATION OF VOID RATIO: The void ratios of the UDS/DS samples were determined at different levels and the results are shown separately.
LIQUID LIMIT & PLASTIC LIMIT: [AS PER IS : 2720 Pt – IV] : The liquid and plastic limit of soils were other index properties of soil have also been determined as per the relevant IS code of practice. The liquid and plastic limits of soil samples have been determined in the laboratory and results are shown separately.
DETERMINATION OF SHEAR PARAMETERS: Un consolidated and un drained Tri-axial shear tests were carried out from soil samples collected as per IS : 2720 Pt – IX 1971 with three different cell pressures of 1,2,3kg/sq.cm using Tri – axial shear testing machine and result are shown separately in tabular and graphical manner.
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P R E F A C E
The general soil profiles and the geological stratification have been determined
OPGC PROPOSED FOR SOIL INVESTIGATION WORK FOR CONSTRUCTION OF CHP
AREA AT MINES END . The objective of this investigation is to ascertain the
characteristics of Sub-soil to present necessary information for sub-surface. It
was endeavored to study in detail the sub-surface conditions at the project site.
.
The field and laboratory works have been conducted as per relevant Bureau of Indian
standards.
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FIELD OPERATIONS In an attempt for optimization in the design of foundation for the proposed building to be
constructed at this site, Geo-technical investigation was done. The entire investigation work had
been divided mainly into two parts (i) Field Work & (ii) Laboratory tests
● Field work determines the types of sub- soil deposit and their characteristics.
● Laboratory tests help in determining the relevant geo-technical properties of the sub-surface
deposited leading to finalization of foundation depth of the structure basing on Bearing capacities
of the foundation strata as well as Influence zone
GROUND WATER TABLE & TERMINATION DEPTH
SL. NO
BORE HOLE NO.
GROUND LEVEL
CHANAGE (M)
TERMINATION DEPTH IN
MTR.
WATER TABLE FROM THE G.L IN
MTR.
1 08 - - 10.0 M 2.3M
2 09 - - 10.0 M 1.8M
3 10 - - 10.0 M 3.3M
BORING & SITU TESTS
Wash boring method was adapted to bores in the soil up to specified depth as mentioned above
below the G.L The SPT were conducted at regular intervals and the samples were brought to the
laboratory with proper identification and labeling standard split spoon sampler was used for
conducting standard penetration test. The number of blows required to drive the sampler for the 1st,
2nd and 3rd 15cm depths were recorded. The total number of blows required to drive the split spoon
sampler due to the free fall of a 663kg. Hammer trough distance of 75cm for the 2nd, and 3rd 15cm
penetration were taken together as the field N-value (penetration resistance) of the soil.
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NOTATIONS C Cohesion Ф Angle of internal fraction of soil DS Disturbed Sample UDS Undisturbed Sample NMC Natural Moisture Content NP Non plastic soil G Special gravity G Gravel Content M Slit Content C Clay Content LL Liquid Limit PL Plastic Limit Pl Plasticity index Cc Compression index K Coefficient of permeability UCS Unconfined Compression N SPT Value BH Bore Hole Suffix The Number of Bore Holes Nc,Nq,Nγ Bearing Capacity Factor Sc,Sq,Sγ S hape factors γ Density of soil D Depth of foundation FS Factor of safety Cv Coefficient of consolidation UU Unconsolidated untrained triaxial test CU Consolidated drained triaxial test GC Clayey Gravels GP Poorly Graded Gravels GW Well Graded Gravels SC Clayey Sand SM Silty Sand SW Wel Graded Sand SP Poorly Graded Sand CH Clays of High Plasticity Cl Clays of Intermediate Plasticity CL Clays of Low Plasticity MH Slits of High Plasticity MI Silts of intermediate Plasticity ML Silts of Low Plasticity
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GUMUDAENGINEERING PROPERTIES OF SOIL PROJECT: MONOHARPUR (BH NO- 10)
\
Sl.
No
.
Sl.
No
.
so
il s
am
ple
co
lle
cte
d a
t
Typ
e o
f s
am
ple
co
lle
cte
d a
t Grain size analysis Atterberg’s Limits
in %
Fie
ld M
ois
ture
Co
nte
nt
in %
Bu
lk D
en
sit
y in
gm
/cc
.
Dry
D
en
sit
y i
n
gm
/cc
.
Co
he
sio
n (
C)
Kg
f/c
m²
An
gle
of
sh
ea
rin
g
res
ista
nce
(Ø
)
In d
eg
ree
Sp
ec
ific
Gra
vit
y
Vo
id R
ati
o
D.F
.S.
in %
Fie
ld S
.P.T
. v
alu
e
Gro
up
of
so
il
Fin
e G
rav
el in
%
Fin
e G
rav
el in
%
(10m
m t
o
4.7
5m
m)
Co
ars
e s
an
d in
%
(4.7
5m
m t
o
2.0
0m
m)
Me
diu
m s
an
d
in %
(2m
m t
o
0.4
25
mm
) F
ine
sa
nd
in
%
(0.4
25m
m t
o
0.0
75
mm
) S
ilt
& C
lay in
%
(0.0
75m
m t
o
0.0
01
mm
) L
iqu
id L
imit
in
%
Pla
sti
c L
imit
in
%
Pla
sti
cit
y In
de
x
in %
1 1.5 SPT 48 7 11 12 22 25 NP
NP
13 - - - - 2.62
- - 36 GM
7.5M TO 8.0M CORE RECOVERY =75 % & RQD = 62 %
8.0M TO 9.0M CORE RECOVERY =81 % & RQD = 78%
9.0M TO 10.0M CORE RECOVERY =82 % & RQD = 78 %
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Data for the safe Bearing capacity calculation:
(NonCohesive Soil)
SPT 'N' = 36 (assumed) unconfined compressive strength qu = N/7.5 kg/cm2
= 26 C = qu/2 = 0.00 T/sq.m
Depth = 1.5 M Ø = 35 degree
Width = 2.0 M yt = 1.82 gm/cc
If the Ø 36 General shear failure
condition is to be considered.
LOCAL SHEAR FAILURE CONDITION
Ø' = tan^ (-1)(0.67x tanØ) = 25.0 Degree
C' = 0.67C = 0.00 T/sq.m
AS PER IS :6403-1981,TABLE-1 = 2.62 (from lab test)
Nc' = 20.72 G = 2.62
Nq' = 10.66 q = Yt X Df
Nγ' = 10.88 = 1.82 X 1.50 = 2.73 T/M² `
By = Width X Yt
2.0 X 1.82 = 3.6 T/M²
AS PER IS :6403-1981,TABLE-2
Sc = 1.0 Sq = 1.0 Sy = 1.0
AS PER IS :6403-1981,5.1.2.2
dc = 1.27 dq = 1.13 dγ = 1.13 (Since ø > 10)
AS PER IS :6403-1981,5.1.2.3
ic = 1 iq = 1 iγ = 1 W = 1.0
1.0
Qult = (C NcSc dc ic)+y.d.(Nq-1)Sq dq iq+1/2 By NySy dy Iy W'
= x 20.72 x 1.0 x 1.27 x 1
+ 2.73 x 9.66 x 1.0 x 1.13 x 1
+ 0.5 x 3.6 x 10.88 x 1.0 x 1.13 x 1.0 x 1.0
= 0.0 + 29.8001 + 22.376
= 52.176 T/M²
Qult = 52.18 T/sq.M
3
SBC = 17.39 T/sq.m
0.000
Assuming the Factor of Safety as =
Based on the above 'N' value the following ' Ø ' values are obtained from the fig.1 of the IS: 6403-1981 less soils (C=0).
And for cohesive soils ( Ø =0) the 'c' value is considered from the relation "
Note:- Where ever the test results are not available the same was assumed based on the available values.
Specific gravity of soil at 1.5 m depth (G)
Assuming the depth factor, shape factor and load inclination factors as unity.
Assuming the water table correction factor (W') as the ultimate bearing capacity is calculated as below:
CADD CONSULTING ENGINEERS (P) LTD Bore hole no:-10GEO - TECHNICAL INVESTIGATION & Sheet No :-7
FOUNDATION ENGINEERING.
Corrected 'N'
NAME OF THE WORK : SOIL INVESTIGATION WORKS FOR MONOHARPUR
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= 2.0 m = 200 cm
= 1.5 m = 150 cm
= 1.0 m
SPT 'N' VALUE OBSERVED = 36
= 26
Due to over burden pressure
As per IS 8009 part I 1976.
Settlement, For 1 kg/cm2 Read from IS 8009
( part I) 1976 Figure - 9 , P.P-17
= 0.0100 m d = ( WT - D)
= 10.00 mm (After applying W') d/b
= 10 mm Adopted water table correction (W')
Premissable settlement = 25 mm
Therefore Allowable Bearing pressure
= 25 / 10
= 2.500 kg/cm2
= 25.00 T/m2
Water table correction(W')
Corrected N value
NAME OF THE WORK:SOIL INVESTIGATION WORKS FOR MONOHARPUR
ALLOWABLE BEARING PRESSURE FOR 25MM SETTLEMENT
Width of footing (B)
Depth of footing (D)
CALCULATION OF ALLOWABLE BEARING PRESSURE BASED ON SPT 'N' VALUE
CADD CONSULTING ENGINEERS (P) LTD BORE HOLE: 10
GEO - TECHNICAL INVESTIGATION & Sheet No : 1
FOUNDATION ENGINEERING.
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= 2.0 m = 200 cm
= 1.5 m = 150 cm
= 1.0 m
SPT 'N' VALUE OBSERVED = 36
= 26
Due to over burden pressure
As per IS 8009 part I 1976.
Settlement, For 1 kg/cm2 Read from IS 8009
( part I) 1976 Figure - 9 , P.P-17
= 0.0100 m d = ( WT - D)
= 10.00 mm (After applying W') d/b
= 10 mm Adopted water table correction (W')
Premissable settlement = 40 mm
Therefore Allowable Bearing pressure
= 40 / 10
= 4.000 kg/cm2
= 40.00 T/m2
Water table correction(W')
Corrected N value
NAME OF THE WORK:SOIL INVESTIGATION WORKS FOR MONOHARPUR
ALLOWABLE BEARING PRESSURE FOR 40MM SETTLEMENT
Width of footing (B)
Depth of footing (D)
CALCULATION OF ALLOWABLE BEARING PRESSURE BASED ON SPT 'N' VALUE
CADD CONSULTING ENGINEERS (P) LTD BORE HOLE: 10
GEO - TECHNICAL INVESTIGATION & Sheet No : 1
FOUNDATION ENGINEERING.
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SUMMARY OF GEOTECHNICAL PARAMETERS & SAFE BEARING CAPACITY
BH
DEPTH
BGL
TYPE
OF
BULK
DENSIT
Y,
SPT-‘N’ ‘N’
CORREC
TION
ARRIVED
ALLOWABLE
BERING
PRESSURE
ALLOWABLE
BERING
PRESSURE
NO (M)SAMPL
Egm/cc VALUE VALUE
C
KG/CM2
Ø
DEGRE
E
SBC T/M²
FOR 25mm
SETTELEMENT
T/M²
FOR 40mm
SETTELEMENT
T/M²
SPT 26
GEO - TECHNICAL INVESTIGATION &
SHEAR
PARAMETERFOOTI
NG IN
M
2X2 361.5 -- -
BH NO :- 10 SHEET NO : 1
NAME OF WORK:- SOIL INVESTIGATION WORKS FOR MONOHARPUR
50.0
CADD CONSULTING ENGINEERS (P) LTD.
10
FOUNDATION ENGINEERING.
25.017.4
-
7.5 M TO 8.0 M
qs = qc x Nj
From laboratory test data
qc = 188 = 1880 T / M2
qs = 1880 x 0 = 188 T / M2
CADD CONSULTING ENGINEERS PVT.LTD.
GEO - TECHNICAL INVESTIGATION &BH NO-10
FOUNDATION ENGINEERING.
LOCATION-MONOHARPUR
DEPTH OF FOUNDATION -
AS PER CI .6 OF IS:12070
Where :
qs = Safe Bearing Pressure (gross)
qc = Average UCS of rock cores
Nj = Empirical coefficient
Including FOS 3
SBC is conservatively Restricted to 80 T / M2
for designed purposed.
Nj = ( 3 + S / Bf ) / (10√(1 + 300 δ / S))
δ = Thickness of discontinues (cm)
S = Spacing of discontinues (cm)
Bf = Footing Width
From table 4 of IS :12070 For spacing of discontinues from 30 cm to 100 cm Nj = 0.1
kg / cm2
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8.0 M TO 9.0 M
qs = qc x Nj
From laboratory test data
qc = 216 = 2160 T / M2
qs = 2160 x 0 = 216 T / M2
CADD CONSULTING ENGINEERS PVT.LTD.
GEO - TECHNICAL INVESTIGATION &BH NO-10
FOUNDATION ENGINEERING.
#REF!
DEPTH OF FOUNDATION -
AS PER CI .6 OF IS:12070
Where :
qs = Safe Bearing Pressure (gross)
qc = Average UCS of rock cores
Nj = Empirical coefficient
Including FOS 3
SBC is conservatively Restricted to 80 T / M2
for designed purposed.
Nj = ( 3 + S / Bf ) / (10√(1 + 300 δ / S))
δ = Thickness of discontinues (cm)
S = Spacing of discontinues (cm)
Bf = Footing Width
From table 4 of IS :12070 For spacing of discontinues from 30 cm to 100 cm Nj = 0.1
kg / cm2
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9.0 M TO 10.0 M
qs = qc x Nj
From laboratory test data
qc = 226 = 2260 T / M2
qs = 2260 x 0 = 226 T / M2
CADD CONSULTING ENGINEERS PVT.LTD.
GEO - TECHNICAL INVESTIGATION &BH NO-10
FOUNDATION ENGINEERING.
#REF!
DEPTH OF FOUNDATION -
AS PER CI .6 OF IS:12070
Where :
qs = Safe Bearing Pressure (gross)
qc = Average UCS of rock cores
Nj = Empirical coefficient
Including FOS 3
SBC is conservatively Restricted to 80 T / M2
for designed purposed.
Nj = ( 3 + S / Bf ) / (10√(1 + 300 δ / S))
δ = Thickness of discontinues (cm)
S = Spacing of discontinues (cm)
Bf = Footing Width
From table 4 of IS :12070 For spacing of discontinues from 30 cm to 100 cm Nj = 0.1
kg / cm2
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BORE HOLE NO -10
SO
AK
ED
UN
SO
AK
ED
7.5m to
8.0m 75% 62% 0.31% 11.7% 5.5 7.8 188 192 87 2.67 2.66 45.5
8.0m
to9.0m 81% 78% 0.31% 11.7% 5.6 9.0 216 222 88 2.67 2.66 45.5
9.0m
to10.0m 82% 78% 0.31% 11.7% 5.9 9.4 226 237 88 2.67 2.66 45.5
NOTE:- Nj = 0.1
qs= S.B.C OF ROCK IN T/M2
qs (qu) X Nj
SBC is conservatively Restricted to 80 T / M2 for designed purposed.
SP
EC
IFIC
GR
AV
ITY
RQ
D %
CO
RE
RE
CO
VE
RY
%
SL
. N
O
SL
AK
E U
DR
AB
ILIT
Y IN
DE
X
(10 m
nts
cycle
)
MO
IST
ER
CO
NT
EN
T (
%)
SO
UN
DN
ES
S
PO
INT
LO
AD
ST
RE
NG
TH
IND
EX
CADD CONSULTING ENGINEERS PVT.LTD.GEO - TECHNICAL INVESTIGATION &
PO
RO
SIT
Y (
MG
/(1+
MG
)X100
FOUNDATION ENGINEERING.
SUMMARY OF FOUNDATION DETAILS OF ROCK SAMPLES
LOCATION:-MONOHARPUR
UN
IT W
EIG
HT
OF
RO
CK
(g/c
c)
HA
RD
NE
SS
(H
,SC
AL
E
MO
HS
)
BO
RE
HO
LE
DE
PT
H O
F F
OU
ND
AT
ION
BG
L (
m)
UN
CO
NF
INE
D
CO
MP
RE
SS
ION
ST
RE
NG
TH
OF
RO
CK
IN
T
/M2
(q
s =
qu
* N
J)
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CADD CONSULTING ENGINEERS PVT.LTD
GEO-TECHNICAL INVESTIGATION & FOUNDATION ENGINEERING.
Sheet No:1
ANALYSIS OF THE SUB SOIL INVESTIGATION TEST RESULT
LOCATION: - MONOHARPUR
BOREHOLE NO- 10
Borehole no- -10 was sunk up to an average depth of 10.0M the sub soil
strata of the Borehole is given in litho logical form and summarized as
follows.
STRATUM
The top layer up to an average depth up to 3.0m consists of Silt
moorum and from 3.0m to 7.5m depth is D.I rock.
The stratum below an average depth from 7.5 m to 10.0 m is consists
of hard rock .
The strata are moderately medium to very dense compact and low to
medium plasticity.
The SPT value tabulated in bore log data sheet.
The core recovery was observed during investigation and tabulated in bore
log data sheet.
The ground water table was encountered at 3.3 m within boring depth.
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FOUNDATION & RECOMMENDATION
Considering the 3 no’s of bore hole and after studying all the engineering
properties it has been decided that depth of foundation can be taken in
suitable depth by digging at least 1.5m inside rock from the original ground
level both for economical point of view and for good structural stability.. But
however the structural designer can adopt higher depth to take advantage of
higher SBC depending upon the load as per decision of designer.
The designer can study the ABP/SBC table for above borehole
and take his own decision as per structural load and position of structure at
the site. The settlement is negligible. Therefore no special care is required for
footing. Single isolated RCC footing can be adopted for framed structure and
for all types of structure.
1. All R.C.C works should be designed as per IS –456-2000
2. Shallow foundation will be designed as per IS: 6403-1981.
3. The groundwater table were encountered and tabulated in Bore log data
in all bore holes.