si report tuas bay drive - urban redevelopment … investigation at tuas bay drive / tuas south ave...
TRANSCRIPT
Soil Investigation at
Tuas Bay Drive / Tuas South Ave 3
For M/s Urban Redevelopment Authority
Purchase Order No. URA000EPO06000714 Issue Date : 08-09-2006
Date: 25th October, 2006
Company Registration No: 198403839N
TABLE OF CONTENT Page
1.0 INTRODUCTION 1
2.0 SCOPE OF WORK 2
2.1 Site Condition 2
2.2 Field Investigation 2
2.2.1 Drilling 2
2.2.2 Standard Penetration Test 2
2.2.3 Undisturbed Sampling 3
2.2.4 Disturbed Sampling 4
2.3 Laboratory Tests 4
2.3.1 Moisture Content 4
2.3.2 Bulk and Dry Density Determination Tests 4
2.3.3 Unconsolidated Undrained Triaxial Compression Test 5
3.0 RESULT OF SOIL INVESTIGATION 5
3.1. Subsoil Condition 5
3.2. Laboratory Tests 7
1
1.0 INTRODUCTION
1.1 General
This report presents the soil investigation based on 5 boreholes, conducted at
the project site, (See location map in APPENDIX-B). The main purpose of the soil
investigation is to obtain and understand the geotechnical information on the subsoil
conditions required for the design and construction works.
a) Name of the Project : Tuas Bay Drive / Tuas South Avenue 3
b) Location : Tuas Bay Drive / Tuas South Avenue 3
c) Client : Urban Redevelopment Authority
d) Period of Work : Field Work
29 September - 18 October, 2006 e) Scope of Work : Field Work
Number of Borehole 5 nos.
Drilling in soil 157.36 m.
Standard Penetration Test (SPT) 52 nos
Undisturbed Sample (UD) 1 nos.
Disturbed Sample (DS) 33 nos.
2
2.0 SCOPE OF WORK
2.1 Site Condition
The project site is located at the vicinity of Tuas Bay Drive and Tuas South
Ave 3. The ground surface at this site behaves a flat and smooth landscape. The key
plan of the project site, including location of the boreholes, is shown in APPENDIX-
B.
2.2 Field Investigation
The field work involved in the geotechnical investigation was carried out as
recommended in BS 5930: 1981 “Code of Practice for Soil Investigation”. Prior to
commencement of the site investigation, trial pit up to 1.5m in depth was conducted at
each borehole before drilling. Summary on quantity of field works for this project is
listed in APPENDIX–A (Table 1).
2.2.1 Drilling
Drilling was carried out using hydraulic feed rotary boring machine. A metal
crown bit as a cutting tool was attached at the lower end of the drilling rods and
circulated mud water was pumped through hollow rods into the bottom of borehole to
wash out the cuttings to ground surface.
5 nos. of boreholes were performed at 5 points namely, BH-1 to BH-5. All
boreholes were terminated when drilling encountered underlying rock and showed
rebounding effect on the drill stem, or as per instruction from the client representatives.
The diameter of the borehole is 100mm. The boring log data is summarized in
APPENDIX-C. In this project, total drilling depth in soil horizon is 157.36m.
2.2.2. Standard Penetration Test
This test is done in accordance with BS 1377: 1990 Part 9 and covers the
determination of the resistance of the penetration of a split-barrel sampler and
obtaining disturbed samples of the soil for identification purpose.
3
It was performed using a split-barrel sampler connected to the lower end of
boring rods. The sampler was driven into soil by means of a 63.5kg hammer falling
freely through a height of 76cm onto an anvil attached to the top of the rods. A trip-
release mechanism and guiding assembly were used to control the falling hammer and
the driving energy was thus transmitted through the rods to the SPT sampler. The
sampler was driven 45cm into soil with the number of blows required for each 15cm
of penetration recorded. The resistance, N-value, was taken as the number of blows
for the last 30cm of penetration.
When 100 blows were reached before the full penetration of 30cm, no further
blows were applied and the final penetration was recorded. At the end of the test, the
sampler was withdrawn and some extracted soil was placed into a plastic container
and then labeled. These samples were used to describe the type of soil existing in the
boring points.
In this project, total 52 numbers of SPT were taken in order to get the
information and technical data on the strength and type of soil (See Table 1).
2.2.3 Undisturbed Sampling
Undisturbed sampling was carried out by using a thin-wall tube sampler with
outer diameter of 75mm. Prior to sampling; the borehole was flushed with water to
remove the remnants left at the bottom of the borehole. The bottom was measured to
confirm the depth at which the soil sample was taken. The sample tube was lowered
down to the bottom of the hole and jacked into soil. After the sample tube was jacked
to the required depth, the sample tube was taken out to the surface. Wax was then
applied to form a seal on both sides of the UD tube and labelled properly before
transporting to the laboratory for testing.
In this project, total 1 number of undisturbed sample was collected at the depth
of 15.0m from BH-4. (See Table 1).
4
2.2.4 Disturbed Sampling
Disturbed samples were taken from a split tube sampler for identification
purpose, and were stored in sealed plastic containers. In this project, 33 number of
disturbed samples were collected. (See Table.1).
2.3 Laboratory Tests
The following Laboratory tests are carried out on the undisturbed samples
obtained from the boreholes. Summary of test results are listed in APPENDIX-D.
- Moisture Content
- Bulk and Dry Density Determination Tests
- Unconsolidated Undrained Triaxial Compression Test
The purpose of laboratory tests is for the evaluation of shear strength,
compressibility characteristics and classification of soil properties. All tests were
carried out in accordance to BS 1377. Classification of soil types is based on the
Unified Soil Classification System (USCS).
2.3.1. Moisture Content
To determine the moisture content of soils, a soil sample is dried at a
temperature of 105°C to 110°C for about 24 hours. The loss in weight of the soil
sample represents the weight of moisture in the soil. The moisture content of the soil
to the dry weight of soil in percentage is the moisture content of the testing soil. This
test if performed in accordance with BS 1377 : Part 2 : 1990 #3.
2.3.2. Bulk and Dry Density Determination Test
The bulk density of a soil is the mass per unit volume of the soil deposit
including any water it contains. The dry density is the mass of dry soil contained in a
unit volume. Both are expressed in Mg/m 3, which is numerically the same as g/cm3. It
was determined at the laboratory by using the linear measurement method approached
by B.S. 1377 : 1990 Part 2 : Test 7:2
5
2.3.3. Unconsolidated Undrained Triaxial Compression Test (UU)
Unconsolidated undrained triaxial compression tests were conducted to
determine the undrained shear strength of the soil. This test is performed with the
drain valve closed for all phases of the test and before the sample has a chance to
consolidate. That is, the undisturbed samples (on 38mm diameter x 76mm length)
are sheared under undrained condition. It is based on the test method approached by
B.S 1377 : 1990 Part 7 : Test 9.
3.0 RESULTS OF SOIL INVESTIGATION
3.1 Subsoil Condition
This section briefly describes the soil conditions encountered at site. Detailed
soil conditions are presented in each log of boring in the Appendices of Borehole Logs.
The summary of borehole data is given in the form of a Generalised Sub-Soil
Profile (see Cross-Sections) which interpolate conditions between boreholes but the
results are not necessarily accurate representations of true conditions on site.
Based on the data collected from 5 number of boreholes, it can be described
that there are 1 layer of back fill soil and 5 types of soil layers predominantly
distributed the project area. The bore log data and their generalized subsoil profiles
are shown in APPENDIX-C.
(1) Fill
(2) Sand / Clayey Sand
(3) Marine Clay
(4) Sand / Silty Clay
(5) Silty Sand
(6) Clayey Silt
(1) Fill
From the surface up to the depth of 1.5 to 2.0 meters was covered with back
fill soil mixed with hardcore materials.
6
(2) Sand / Clayey Sand
This layer comes after the top most back fill soil and can be seen in all bore
holes except BH-5. It consists of very looses to loose, light grey to yellowish brown,
occasionally greenish yellow, reclaimed Sands and Clayey Sand, with shell
fragments. Thickness is about 7.0 to 10.0 meters. SPT 'N' values ranged from 3 to 9
blows.
(3) Marine Clay
This layer is one of the major soil types occupied in this area and can be seen
in all bore holes. It consists of very soft to soft, bluish grey, Marine Clay, with traces
of sand. Thickness is about 3.0 to 12.0 meters and SPT 'N' values showed 0 to 5
blows.
(4) Sand / Silty Clay
This layer lies under the marine clay layer and can be seen in all bore holes
except BH-4. It consists of stiff to hard, yellowish to reddish brown, grey to dark
grey, Silty Clay. Thickness is about 3.0 meters and SPT 'N' values ranged from 9 to
69 blows. A pocket of very dense, reddish brown, Sands, with traces of clay, was
encountered at the depth of 15 to 18 meters in BH-1 and SPT 'N' values registered at
61 blows
(5) Silty Sand
This layer and can be seen only in BH-1 and BH-2. It consists of very dense,
bluish grey to grey, Silty, fine Sand. Thickness is about 3.0 to 9.0 meters and SPT 'N'
values showed 71 to 100 blows.
7
(6) Clayey Silt
A thick layer of this soil type can be seen in all bore holes. It consists of hard,
bluish grey to dark grey, occasionally purplish brown, Clayey Silt. Apparent thickness
is about .04 to well over 9.0 meters. But true thickness can not be estimated as the
bore holes were terminated in this layer. SPT 'N' values ranged from 42 to 100 blows.
General Geology
Based upon the Geological Map of Singapore by PWD (1974) and the present
investigation, a layer of back fill soil, man made reclaimed [Sands / Clayey Sand],
[Marine Clays] of 'Marine' member and [Sands / Silty Clays] of 'Alluvial' member
from "Kallang Formation", followed by completely weathered to decomposed
underlying sedimentary rocks from "Jurong Formation", such as: [Silty Sand, Clayey
Silt] are well distributed at the project site.
3.2 Laboratory Tests
Summary of laboratory test results and details of individual test results are
shown in the APPENDIX-D.
APPENDIX - A
TABLES & CHARTS
CLIENT : URBAN REDEVELOPMENT AUTHORITYPROJECT : TUAS BAY DRIVE / TUAS SOUTH AVENUE 3TABLE 1. : SUMMARY ON QUANTITY OF FIELD INVESTIGATION
Mech-anic
(Nos)
Hydro (Nos)
UU* (Nos)
CU* (Nos)
BH 1 13-10-06 18-10-06 104.420 30.40 30.40 - 10 6 - - - - - - - - - - - -BH 2 13-10-06 17-10-06 104.450 33.07 33.07 - 11 8 - - - - - - - - - - - -BH 3 09-10-06 11-10-06 104.440 27.23 27.23 - 9 7 - - - - - - - - - - - -BH 4 29-09-06 06-10-06 104.480 33.25 33.25 - 11 7 1 1 1 - - - - 1 - - - -BH 5 09-10-06 12-10-06 104.400 33.41 33.41 - 11 5 - - - - - - - - - - - -
157.36 157.36 0.00 52 33 1 1 1 0 0 0 0 1 0 0 0 0Note :SPT = Standard Penetration Test UD = Undisturbed Sample CU = Consolidated Undrained Triaxial TestDS = Disturbed Sample UU = Unconsolidated Undrained Triaxial Test
pH (Nos)
SO3
(Nos)CL-
(Nos)
Reduce Level (m)
Total Depth of Bore
Hole (m)
Period of Fieldwork
SPT(Nos)
Insitu Test & InstallationChemical Test
Bore Hole No.
Physical Test Mechanical TestTriaxial Tests
Laboratory Test
Grain Size
Commence CompleteAtter-berg Limit (Nos)
Specific Gravity (Nos)
Bulk/Dry Density (Nos)
Moisture Content (Nos)
Depth of Drilling in
Soil (m)
DS (Nos)
UD (Nos)
Depth of Coring in
Rock (m)
Client : Urban Redevelopment AuthorityProject : Tuas Bay Drive / Tuas South Avenue 3
Location : Tuas Bay Drive / Tuas South Avenue 3
TABLE 2. MONITORING RECORD FOR WATER LEVEL AT BOREHOLE (During Operation)
14-10-06 8:30 AM 15.00 2.5016-10-06 8:30 AM 27.00 2.4218-10-06 8:30 AM 30.00 2.5614-10-06 8:30 AM 15.00 2.5016-10-06 8:30 AM 27.00 2.5417-10-06 8:30 AM 33.00 2.5711-10-06 8:30 AM 21.00 2.60
30-09-06 8:30 AM 9.00 2.8002-10-06 8:30 AM 15.00 2.7603-10-06 8:30 AM 18.00 2.7805-10-06 8:30 AM 30.00 2.7306-10-06 8:30 AM 33.00 2.7710-10-06 8:30 AM 6.00 2.8011-10-06 8:30 AM 24.00 2.8212-10-06 8:30 AM 33.00 2.80
BH 5
Water Level (m)
Borehole Number Date Time Borehole Depth (m)
BH 1
BH 2
BH 3
BH 4
APPENDIX - B
LOCATION PLAN
APPENDIX - C
BOREHOLE LOG
KEY TO BORING LOG
BORE HOLE LOG
( BH-1 to BH-5 )
GENERALIZED SOIL PROFILE
( CROSS _ SECTIONS )
APPENDIX - D
LABORATORY TEST RESULTS
Summary of Laboratory Test Results
SUMMARY OF LABORATORY TEST RESULTS
UCT
Borehole Sample Depth No. No. (m)
UD1 15.00-15.50 2.01 1.56 29 97 0
Client: M/s Urban Redevelopment Authority * Multi Stage UCT - Unconfined Compression Triaxial TestLocation: Tuas Bay Drive / Tuas South Ave 3 ^ Field Vane UU - Unconsolidated Undrained Triaxial Compression TestProject: Tuas Bay Drive / Tuas South Ave 3 ~ Lab. Vane CU - Consolidated Isotropic Undrained Triaxial Compression Test
CD - Consolidated Isotropic Drained Triaxial Compression Test
BH 5
BH 1
BH 2
BH 3
BH 4
Bul
k D
ensi
ty (M
g/m
3 )
Liqu
id L
imit
(%)
Pla
stic
Lim
it (%
)
Pla
stic
ity In
dex
(%)
Spec
ific
Gra
vity
Moi
stur
e C
onte
nt (%
)
Atterberg Limit
Dry
Den
sity
(Mg/
m3 )
CD
Gra
vel (
%)
San
d (%
)
Silt
(%)
Coh
esio
n (k
N/m
2 )
Coh
esio
n (k
N/m
2 )
Coh
esio
n (k
N/m
2 )
Phi
Ang
le (
o )
Grain Size Distribution
Cla
y (%
)
Water
pH V
alue
pH V
alue
Sul
phat
e C
onte
nt in
Chl
orid
e C
onte
nt
2:1
wat
er:s
oil e
xtra
ct
Sal
inity
Sul
phat
e C
onte
nt
Pre
cons
olid
atio
n P
ress
ure
(kN
/m2)
Vane
Phi
Ang
le (
o )
UU CU
Rem
ould
ed S
hear
S
treng
th (k
N/m
2)
Triaxial Compression
Coh
esio
n (k
N/m
2 )
Initi
al V
oid
Rat
io
Phi
Ang
le (
o )
Com
pres
sion
Inde
x
Und
istu
rbed
She
ar
Stre
ngth
(kN
/m2)
Con
tent
(%)
Unc
onfin
ed C
ompr
essi
on
Test
- R
ock
Cor
e (M
pa)
Tota
l Sul
phat
e
Chemical Soil
Consolidation
Moisture Content / Bulk Density
Unconsolidated Undrained Triaxial Compression Test