urban redevelopment authority

URBAN REDEVELOPMENT AUTHORITY TERM CONTRACT FOR SOIL INVESTIGATION (URA/T/13/010)

Soil Investigation Works At Tampines Road /Upper Serangoon Road

Report No: ECGP 2531 URA ECON GEOTECH PTE LTD

CCOONNTTEENNTTSS VOLUME I

PPaaggee NNoo..

1.0 INTRODUCTION 005

1.1 General 005

2.0 FIELD WORKS 006

2.1 General 006

2.2 Description of Field Investigation 006

2.2.1 Drilling 006

2.2.2 Undisturbed Sampling 006

2.2.3 Standard Penetration Testing 006

3.0 LABORATORY TESTING 007

3.1 General 007

3.2 Code of Practice 007

3.3 Physical Properties 007

3.3.1 Moisture Content 007

3.3.2 Bulk and Dry Density 007

3.3.3 Particle Density 007

3.3.4 Atterberg Limit 007

3.3.5 Grain Size Analysis 007

3.4 Mechanical Properties 008

3.4.1 Unconsolidated Undrained (UU) Triaxial Test 008

3.4.2 Consolidated Undrained (CU) Triaxial Test 008

3.5 Summary of Laboratory Test Results for Soils 008

4.0 SOIL CLASSIFICATION 009

5.0 LIST OF GEOLOGICAL CROSS-SECTIONS 009

6.0 DESCRIPTION OF SOIL STRATA 009-010

REFERENCES 011

3

URBAN REDEVELOPMENT AUTHORITY TERM CONTRACT FOR SOIL INVESTIGATION (URA/T/13/010)

Soil Investigation Works At Tampines Road /Upper Serangoon Road

Report No: ECGP 2531 URA ECON GEOTECH PTE LTD

LLIISSTT OOFF TTAABBLLEESS

Table 1.1 Quantity of Field Works and Laboratory Tests 012

Table 2.1 Classification / Symbol of Soil and Rock Type 013

Table 2.2 Geological Stratigraphy of Singapore 014

Table 2.3 Identification and Description of Soils 015

Table 2.4 Weathering Classification of Soils / Rocks 017

Table 2.5 Plasticity Chart 018

Table 2.6.1 Classification of Clays/Silts from Shear Strength 019

Table 2.6.2 Classification of Clays/Silts from SPT results 019

Table 2.6.3 Classification of Sands from SPT Results 019

LLIISSTT OOFF FFIIGGUURREESS

Fig. 1 Illustration of Boring Work 020

Fig. 2 Illustration of Standard Penetration Test 021

AAPPPPEENNDDIICCEESS

APPENDIX AA

· Location Plan 023

· Borehole Location Plan 024

· As-built Borehole Locations 025

· Cross-Sections 026

· Legends for different soil and rock types 027

· Borehole Logs 028-037

APPENDIX BB

· Laboratory Test Results of Physical & Mechanical

Properties of Soil Samples 039-154

· Certificate of Accreditations 155

aaõõbb

4

1.0 INTRODUCTION

1.1 General

On behalf of Urban Redevelopment Authority, Econ Geotech Pte Ltd has performed the Term Contract for Soil Investigation (URA/T/13/010). This report presents the factual results of Soil Investigation Works At Tampines Road and Upper Serangoon Road. The field investigation for this project was carried out between 26th June 2014 and 17th July 2014. The works described here in this report have been carried out as per the specifications and under the technical direction of the client. This report covers 5 boreholes.

The particulars of this project are as follows:

(a) Name of Project Soil Investigation Works At Tampines Road /Upper Serangoon Road

(b) Location Tampines Road /Upper Serangoon Road

(c) Client Urban Redevelopment Authority

(d) Main Contractor ECON Geotech Pte. Ltd.

(e) Director Steven Ih Yeo

(f) Project Manager Aung Moe

(g)

Period of Work Field Works

v 26th June 2014 – 17th July 2014

Laboratory Works and Report

v 17th June 2014 – 16th Aug 2014

(h) Scope of Work Field Works

Ø Boreholes

5 Locations

Laboratory Tests Moisture Content, Bulk & Dry Density,

Grain Size Analysis, Atterberg Limit

Tests, Triaxial (UU) and (CU) Tests of

Soil Samples.

(Refer Table 1.1 & 1.2 for Quantities of Field and Laboratory Works)

5

2.0 FIELD WORKS

2.1 General

The field works were generally carried out in accordance with BS 5930: 1999 “Code of Practice for Site Investigation” and as directed by the client.

The Borehole Location Plan for proposed site investigation works is shown in AAppppeennddiixx--AA.. The co-ordinates and reduced levels of the boreholes are also presented in respective borelogs in AAppppeennddiixx--AA..

2.2 Description of Field Investigation

2.2.1 Drilling

This investigation was performed using rotary drilling rig. A cutting tool was attached to the drilling rod to drill through the soils, which produces 100mm diameter borehole. Circulated mud water was pumped through the hollow rods into the hole to stabilize the borehole and to wash out the soil debris (resulted due to drilling) to the ground surface by pressure. Partial casing was used to stabilize the borehole side apart from using mud circulation. Trial pits of size 1.0 x 1.0 x 3.0 m depth was generally excavated at every borehole location. The boreholes were terminated at the depths as suggested by the client. Illustration of Boring works is shown in (Fig.2.1). During the investigation, a site log was kept by the Geotechnical site supervisor to record soil descriptions, stratum changes, SPT and coring field records.

2.2.2 Undisturbed Sampling

Undisturbed samples were generally collected at the depth of 3 m intervals in Kallang Formation, unless otherwise specified by the client. Before a sample was taken, the bottom of the borehole was cleaned. Each sample was then collected using a 75 mm diameter by 1000 mm long 'Shelby' type thin wall sample tube driven by hydraulic push. Samples of very stiff to hard soil were collected by using Mazier sampler. Thin wall piston samplers were used for very soft to soft soil. After a sample was retrieved from borehole, it was immediately labeled and sealed with wax at both ends before sending to laboratory.

2.2.3 Standard Penetration Testing

Standard Penetration Tests (SPT) is generally performed at 3m interval in all soil layers, as it is shown in (Fig.2.2). Once the borehole reached the required test depth, the borehole was cleaned by flushing with water/mud before starting the test. The test was performed by using a split barrel type sampler with a 50.8 mm external and 34.9 mm internal diameter. The test was conducted in six stages, where each stage consisted of driving the sampler 75 mm into the soil by the use of a free fall 63.5 kg hammer (or monkey). The hammer was dropped from a height of 760 mm on to an anvil connected to the sampler by rods. The number of blows required for each 75mm penetration was noted and the final N-value is reported as the total number of blows required to achieve the last 300 mm of penetration, the initial 150 mm of penetration being to seat the sampler and by-pass any disturbance. If, however, 100 blows were reached before a penetration of 300 mm was achieved, the test was stopped and the penetration achieved recorded.

6

3.0 LABORATORY TESTING

3.1 General

The various laboratory tests were performed on undisturbed samples based on the testing schedule approved by the consultant. The tests related to mechanical properties were performed in Econ Geotech Laboratory. The quantities of laboratory tests are summarized in TTaabbllee 11..22

3.2 Code of Practice

The laboratory tests were performed in accordance with the British Standard Code of Practice BS 1377 (1990) and as per terms of accreditation under the Singapore Accreditation Council – Singapore Laboratory Accreditation Scheme. The summaries and detailed test results are presented in Appendix-B. The results are also presented in respective borehole logs in AAppppeennddiixx--AA.

3.3 Physical Properties

3.3.1 Moisture Content

To measure moisture content, a weighed specimen is taken from an undisturbed sample and placed in a tin, where it is oven dried at 105-110◦C for 18-24 hours. The soil is weighted after the drying and the weight of water is calculated simply by subtracting the two values. The moisture content is then defined as the percentage of the weight of water over weight of dry soil.

3.3.2 Bulk and Dry Density

The bulk density is the measured weight of a solid cylindrical soil specimen taken from an undisturbed sample divided by its volume. The dry density was calculated from bulk density and moisture content.

3.3.3 Particle Density

The particle density of a specimen is determined in accordance to BS 1377 using an oven dried representative portion of the undisturbed sample. The particle density is defined as the ratio of the weight of soil to the water needed to displace the soil particles.

3.3.4 Atterberg Limit

The liquid limit of a specimen is derived using the cone penetrometer method as to BS 1377. The plastic limit is defined as the moisture content of a specimen at the point where it can be satisfactorily rolled into a 3mm diameter thread with just starting to crumble. The soils’ plasticity index is then derived by subtracting the plastic limit from the liquid limit.

3.3.5 Grain Size Analysis

The grain size analysis has been carried out utilizing both sieve and hydrometer analysis.The sieve analysis was carried out by wet sieving method in which the material was first washed through a 2 mm test sieve nested in a 63 mm test sieve. The soils retained in the sieves were then dried in an oven. The dried soils were then sieved by dry sieving by passing the soils through a series of square mesh sieves, which become progressively finer down to 63 mm mesh. Each fraction

7

thus collected was then weighed and the percentage retained on each sieve was calculated by dividing individual weights by the total sample weight. The soils passing through 63 mm mesh was analyzed by sedimentation using hydrometer method. The hydrometer method involves measuring the rate of settlement of fine particles suspended in a solution. Utilizing the principle of Stokes’ law, particle size can be directly related to its rate of settlement in a fluid such as water. From this process, the particle diameter and percentage finer is calculated.

3.4 Mechanical Properties

3.4.1 Unconsolidated Undrained (UU) Triaxial Test

This test is generally performed as a set of three single stage tests (UU). However, if the sample is not enough, the test is conducted using two or single (multistage) specimen. The general testing procedure is as explained below.With the three single stage tests, three specimens were extracted from a single undisturbed sample, and was trimmed and cut to a length to diameter ratio is about two. The specimens were then weighed before putting the rubber membrane and placing into triaxial cell. Cell pressures of 0.5sv, sv, and 2sv (where sv is total overburden pressure at the sampling depth) were applied to the three specimens followed by shearing under undrained conditions at a constant rate of strain (usually 2% per minute). Axial load and displacement were recorded at regular intervals until a maximum deviator stress, or 20% of strain is reached. For tests with two specimens, cell pressure of sv and 2sv were used.

3.4.2 Consolidated Undrained (CU) Triaxial Test

The CU test was carried out in three stages, e.g., saturation, consolidation and shearing. In the first stage, the sample was saturated by applying backpressure. The sample was then consolidated in the triaxial cell, with the drainage valves open, under the confining pressure to bring the specimen to the state of effective stress required for carrying out the compression test. After consolidation, the specimen was sheared under undrained condition. The shearing stage was similar to unconsolidated undrained (UU) test, but with much lower rate of strain to allow for the pore pressure to equalize. The pore pressure was measured during the shearing stage thus enabling the determination of effective stress parameters.This test is generally performed as a set of three single stage tests. However, if the sample is not enough, the test is conducted using two or single (multistage) specimen. The three cell pressures correspond to 0.5s¢v, s¢v, and 2s¢v, where s¢v is effective overburden pressure. For a multistage test, the shearing was stopped when the peak deviator stress was imminent, and the consolidation and shearing stages were repeated for the next cell pressure.

3.5 Summary of Laboratory Test Results for Soils

Laboratory tests were generally performed in accordance with the British Standards Code of Practice BS 1377 (1990). The tests were carried out on undisturbed samples to determine the physical, mechanical and chemical properties.Details results of physical and mechanical properties of soil for each geological classification are presented in AAppppeennddiixx--BB. Summaries of test results are also presented respectively.

8

4.0 SOIL CLASSIFICATION

The soil classification is based on the geological classification and British classification system as given in AAppppeennddiixx--AA. The consistencies of clay/silt and relative densities of sand have been classified according to the (BS5930: 1999). Classification of sand, clay and silt from SPT and Shear Strength are presented in (Table 2.9.1 to 2.9.3).

5.0 LIST OF GEOLOGICAL CROSS-SECTIONS

Geological cross-sections showing the soil strata profile at the borehole locations are presented in AAppppeennddiixx--AA..

SECTION BOREHOLES

1 BH1 – BH2 – BH3 – BH4 – BH5

6.0 DESCRIPTION OF SOIL STRATA

The geologic material encountered during site investigation can be briefly described as follows. Based on the borehole data in-situ tests results obtained from the boreholes, the underlying sub-soils can be sub-divided into the following layers:

- BACKFILL

- KALLANG FORMATION

- OLD ALLUVIUM

BACKFILL

Backfilled soils are manmade deposits of natural earth materials. The backfill were found as the topmost layer in every borehole. Backfill consisted heterogeneous soils of very soft to soft, light brownish yellow and light reddish orange, yellowish brown , slightly gravelly sandy SILT / sandy CLAY and loose, yellowish brown to reddish white sitlty / clayey fine to coarse grained SAND with concrete and rock fragments.

KALLANG FORMATION

The Kallang Formation includes the sedimentary deposits found along the coast line and extends to the head waters of river draining in Singapore.The deposits are generally low lying and are seldom recognized more than 4 m above sea level except in the more inland areas

Two members are recognized within the formation referred to informally as the, Alluvial Member, and Transitional Member.

9

Fluvial _ Cohesive Soil (F1)

This soil type was encountered in four boreholes, BH1, BH-2, BH-3 and BH4.

This soils observed in the present investigation consist of very loose to loose, slightly gravelly silty fine to coarse SAND and silty / clayey fine to coarse SAND. The colour of these soil layers are yellowish brown and reddish brown.

Fluvial – Cohesive Soils (F2)

This soils observed in the present investigation consist of stiff sandy SILT / CLAY. The colour of these soil layers light red and light brownish yellow and reddish brown.

Estuarine (E)

Peaty SILT / CLAY with sand and decomposed wood were observed in two boreholes. The color of soil is generally dark grey to dark brown.

OLD ALLUVIUM ( O )

The Old Alluvium is alluvial deposit that has been variably cemented and has the strength of very weak to weak rock. The upper zone of the Old Alluvium has been affected by weathering. Over-consolidation, compaction and lithification of sediments in Old Alluvium can be differentiated from those of Kallang Formation. The Old Alluvium mainly consists of Sandy SILT/CLAY and Clayey/Silty/Gravelly fine to coarse SAND. The color of soil is generally light bluish grey, light greenish grey, yellowish/reddish brown, and brownish grey.

Residual (O (E), SPT-N<10) was observed in two boreholes, BH1 and BH5 consists of loose, yellowish brown and grey, slightly gravelly very clayey fine to coarse SAND.

Destructured (O (D), SPT-N 10 to 30) was observed in four boreholes. It consists of gravelly very clayey fine to coarse SAND, silty fine to medium SAND and sandy CLAY.

Distinctly Weathered (O (C), SPT-N 30 to 50) was also observed at four boreholes, BH2, BH3, BH4 and BH5. This layer consists of CLAY, Sandy CLAY/SILT and slightly sandy CLAY/SILT. Color varies from light brown to reddish brown and light bluish grey.

Partially Weathered (O (B), SPT-N > 50) was observed at four boreholes, consists of very dense, greenish grey and light greenish slightly gravelly silty fine to coarse SAND and hard, greenish grey spotted white, sandy SILT.

Unweathered (O (A), SPT-N >50) was found in all boreholes, color was light

greenish grey, very dense slightly silty fine to medium SAND and greenish brown

spotted white, sandy SILT / CLAY.

10

REFERENCES

1. BS 5930: 1999. “Code of Practice for Site Investigation”, British

Standard Institution.

2. Braja M. Das, 1994. Principles of Geotechnical Engineering, Third

Edition. PWS Publishing Company, Boston

3. Coduto, Donald P, 1994. Foundation Design: Principles and Practices.

Pentice-Hall, New Jersey.

4. Karl Terzaghi, Ralph B. Peck and Gholamreza Mesri, 1996. Soil

Mechanics in Engineering Practice, Third Edition.

5. Michael Carter and Stephen P Bentley, 1991. Correlations of Soil

Properties. Pentech Press, London.

6. P.W.D., 1976. “The Geology of the Republic of Singapore”, Public Works

Department, Singapore.

7. DSTA, 2009. “Geology of Singapore”, 2nd ed., Defense Science and

Technology Agency, Singapore.

11

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12

REFERENCE SOIL & ROCK TYPE GENERAL DESCRIPTION GEOLOGICAL

FORMATION (PWD, 1976)

B BEACH (Littoral) Sandy, sometimes silty, with gravels, coral and shells

KALLANG Littoral, possibly also part of all other members& TEKONG

E ESTUARINE (Transitional)

Peats, peaty and organic clays, organic sands KALLANG Transitional, possibly part of Alluvial andMarine.

F FLUVIAL (Alluvial)

Sands, silty sands, silts and clays KALLANG Alluvial, possibly part of all othermembers and TEKONG.

F1 Predominantly granular soils including silty sands, clayey sands and sandy silts

Bed of Alluvial Member of KALLANG

F2 Cohesive soils including silty clays, sandy clays and clayey silts

Bed of Alluvial Member of KALLANG

M MARINE Very soft to soft blue or grey clay KALLANG Marine Member

O OLD ALLUVIUM Very weak to weak beds of sandstone and mudstone. See C-5 for weathering classification

OLD ALLUVIUM

FC FORT CANNING BOULDER BED (also known as S3, Bouldery Clay or Boulder Bed)

A colluvial deposit of boulders in a soil matrix. The matrix is typically a hard silty clay, but can be granular. The material is largely derived from the rocks and weathered rocks of the Jurong Formation

Not shown in PWD (1976)

S SEDIMENTARIES (Rocks & associated soils)

Sandstones, siltstones mudstones, conglomerate and limestone. The rockhas been subjected to a varying degree ofmetamorphism.

JURONG Tengah, Rimau, Ayer Chawan and Queenstown Facies (plus the Pandan Limestone, which was not identified in PWD (1976)

G GRANITE (Rock and associated Residual soils)

Granitic rocks, including granodiorite, adamellite and granite.

BUKIT TIMAH GRANITE

C-3 Classificatiion/ Symbol of Soil and Rock Type

13

Econ

Text Box

Table 2.1

Geological Time Series/Stage Description of stratum

Era Period Epoch Formation Stratum Zone Symbol Particular Origin

Time Bp-year

First Organic Clay

Au (O1) Consists mainly decomposed organic material. Very soft & high water content.

Deposit of limnetic brackish water

First Sand

Au(S1) Poor graded medium grain loose sand with some shell fragments.

Deposited at beach and shallow water depth of sea.

Marine Clay

Au(M) Very soft high water content and high plasticity clay.

Seabed deposit at 5-30m depth drowned valley.

First Cohesive soil

Au(C) Very soft high water content clayey silt with sand.

Deposit of limnetic-half brackish water.

Second Organic Clay

Au(O2) Very soft decomposed organic matter with clay.

Deposit of limnetic-half Brackish water.

Second Sand

Au(S2) Well graded sand with some organic. Deposit at shallow water depth..

6000 -

10000

Brown Clay

AL(B) Lower water content stiff clay. Thickness varies at each location.

Alteration by weathering oxidation.

Third Sand

AL(S1) Medium dense fine to medium grained sand Deposit at shallow sea water depth or beach.

Lower Marine Clay

AL(M) Soft and high plasticity homogeneous clay with shell fragments.

Seabed deposit at 5-30m depth drowned valley.

Second Cohesive Soil

AL(C) Soft to firm high plasticity clayey silt with fine sand.

Deposit of limnetic-half brackish water.

Third Organic Clay

AL(O) Soft low water content organic clay. Deposit at shallow water depth.

Fourth Sand

AL(S2) Well graded sand with some gravel and organic material

Shallow seabed deposit.

11000

- 15000

Weathered Zone OA(W) Weaken and alteration by weathering/ oxidation.

Cemented Zone OA(C)

Irregular alternating layers of well graded sandy soil and clayey silt. Very Dense and hard by cementation.

Materials is very hard & dense by chemical/ diagenesis.

Approx 3.5-5.0 x 104

Weathered Zone Bc(W)

Cemented Zone Bc(C)

Very hard reddish brown clay with various sizes of strong sandstone boulder. Size of boulder ranges from 10-45cm.

Produce of fault as fault clay and fault breccia and cemented during some geological period.

Residual Soil

J(R) Wholly decomposed material by weathering.

Completely Weathered Zone

J(C) Decomposed material by weathering.

Highly Weathered Zone

J(H) Weak and friable material by weathering

Moderately Weathered Zone

J(M) Materials weakened near joint surface by weathering.

Slightly Weathered Zone

J(S) Many joints developed with some weathering at joint surface.

Fresh Zone J(F)

Constituted of alternating sandstone, mudstone and conglomerate. Limestone developed as thin layers. Many fault zones are found and material near the granite area is disturbed. Thermal metamorphism occurs near the granite zone.

Strong massive rock.

Approx2.0x108

-

2.1x108

Residual Soil

G(R Wholly decomposed material to soil.

Completely Weathered Zone

G(C) Decomposed weak material by weathering.

Highly Weathered Zone

G(H) Weak and friable material by weathering.

Moderately Weathered Zone

G(M) Material is weak near the joint.

Slightly Weathered Zone

G(S) Joints developed with some weathering at joint surfaces.

Fresh Zone G(F)

Coarse-grained granodiorite and biotite granite. Contains porphyrite and lamprophyre as dike. Two types of fault system are found to develop.

Strong massive rock.

Approx2.1x108

-

2.2x108

C-2 Geological Stratigraphy of Singapore (M.W. TAN & A.WADA, 11TH S.E ASIAN GEOTECH.

CONF., 4-8 MAY, 1993)

Upper Alluvium

Lower Alluvium

Old Alluvium

Boulder Clay

Jurong Formation

Bukit Timah Granite

Holocene

Pleistocene

Jurassic- Initial

Late

Middle

Initial

Triassic

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c

Tertiary__ Unknown__

Quarter nary

Cen

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c

14

Econ

Text Box

Table 2.2 Geological Stratigraphy of Singapore (M.W TAN & A.WADA, 11TH S.E ASIAN GEOTECH. CONF., 4-8 MAY, 1993)

Econ

Text Box

Ver

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C-4 Identification and Description of Soil (BS 5930, 1999)

15

Econ

Text Box

Table 2.3 Identification and description of soils (BS 5930, 1999)

Table 3.2 Identification and description of soils (continued)

BOULDERS Only seen complete in pits or exposuresCOBBLES Often difficult to recover whole from boreholes

ALLUVIUM,

using terms such as; WEATHERED BRACKLESHAMCLAY,

with rare

with occasional LIAS CLAY,

with abundant/frequent/ numerous

TOPSOIL,

Notesa) Or described as coarse soil depending on mass behaviour d) Gravelly sandy and/or silty or clayey

b) Or described as fine soil depending on mass behaviour e) Gravelly and/ or sandy

c) %coarse or fine soil type assessed excluding cobbles and boulders f) Gravelly of sandy

Example descriptions

Easily visible to naked eye: particle shape can be described: grading can be described.GRAVEL

SAND Visible to naked eye: no cohesion when dry: grading can be described.

Medium dense light brown gravelly clayey fine SAND, Gravel is fine (GLACIAL DEPOSITS)

PRINCIPALSOIL TYPE Visual identification Minor constituents Stratum name

Dry lumps can be broken but not powdered between the fingers; they also disintegrate under water but more slowly than silt; smooth to the touch; exhibits plasticity but no dilatancy; sticks to the fingers and dries slowly; shrinks appreciably on drying usually showing cracks.

CLAY

SILT

Only coarse silt visible with hand lens; exhibits little plasticity and marked dilatancy: slightly granular or silky to the touch; disintegrates in water; lumps dry quickly; possesses cohesion but can be powdered easily between fingers

Intermediate in behaviour between clay and silt. Slightly dilatantCLAY/SILT

Shell fragments, pockets of peal, gypsum crystals, flint gravel, fragments of brick, rootlets, plastic bags etc

%defined on a site or material specific basis or subjective

MADE GROUND OR GLACIAL DEPOSITS? etc.

EMBANKMENTFILL,

RECENTDEPOSITS,

Stiff very closely sheared orange mottled brown slighlty gravelly CLAY. Gravel is fine and medium of rounded quartzite. (REWORKED WEATHERED LONDON CLAY)

Plastic brown clayey amorphous PEAT (RECENT DEPOSITS)

Firm thinly laminated grey CLAY with closely spaced thick laminae of sand (ALLUVIUM)

Loose brown very sandy sub-angular fine to coarse flint GRAVEL with small pockets(up to 30mm)of clay. (TERRACE GRAVELS)

16

Econ

Text Box

Table 2.3 Identification and description of soils (continued)

Table 2.4 WEATHERING CLASSIFICATION OF SOILS / ROCKS

Weathering Classification (Bukit Timah Granite and Gombak Norite)

Grade Basis for assessment

G(I) Intact strength, unaffected by weathering. Not broken easily by hammer – rings when struck. No visible discoloration.

G(II) Not broken easily by hammer – rings when struck. Fresh rock colors generally retained but stained near joint surfaces.

G(III) Cannot be broken by hand. Easily broken by hammer. Makes a dull or sight ringing sound when struck with hammer. Stained throughout.

G(IV) Core can be broken by hand. Does not slake in water. Completely discolored.

G(V) Original rock texture preserved can be crumbled by hand. Slakes in water. Completely discolored.

G(VI) Original rock structure completely degraded to a soil with none of the original fabric remains. Can be crumbled by hand.

Weathering Classification for Jurong Formation (Except Pandan Limestone)

Grade Basis for assessment

S(I) Intact strength, unaffected by weathering

S(II) Slightly weakened, slight discoloration, particularly along joints.

S(III) Considerable weakened & discolored, but larger pieces cannot be broken by hand. RQD is generally >0, but RQD should not be used as the major criterion for assessment.

S(IV)

Core can be broken by hand or consists of gravel size pieces. Generally highly to very highly fractured, but majority of sample consists of lithorelics. RQD generally = 0, but RQD should not be used as major guide for assessment. For siltstone, shale, sandstone, quartzite and conglomerate, the slake test can be used de differentiate between Grade IV (does not slake).

S(V) Rock weathered down to soil-like material, but bedding intact. Material slakes in water

S(VI) Rock degraded to a soil in which none of the original bedding remains.

Weathering Classification for Old Alluvium

Class Classifier Characteristics Indicative SPT, Blow/300mm*

A Unweathered Original strength

B Partially Weathered Slightly reduced strength

>50(cannot usually be penetrated by CPTs with 20t load capacity)

C Distinctly weathered Further weakened 30 to 50

D Destructured Greatly weakened, often mottled, bedding disturbed

10 to 30

E Residual No bedding remains <10

* The SPT result should not be used in isolation to assess weathering.

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Econ

Text Box

Table 2.5

Undrained Shear Strength (kPa) Consistency

< 20 Very Soft

20 – 40 Soft

40 – 75 Firm

75 – 150 Stiff

150 – 300 Very Stiff

> 300 Hard

Table 2.6.1 Classification of Clays/Silts from Shear Strength (BS5930: 1999)

Approximate Relation of Consistency to SPT

N-Value (blows/300mm of penetration) Consistency

< 2 Very Soft

2 – 4 Soft

4 – 8 Firm

8 – 15 Stiff

15 – 30 Very Stiff

> 30 Hard

Table 2.6.2 Classification of Clays/Silts from SPT results (Terzaghi and Peck)

Approximate Relation of Relative Density to SPT

N-Value (blows/300mm of penetration) Relative Density

< 4 Very Loose

4 – 10 Loose

10 – 30 Medium Dense

30 – 50 Dense

> 50 Very Dense

Table 2.6.3 Classification of Sands from SPT results (BS5930: 1999)

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Fig. 1. Illustration of Boring Work

20

Fig. 2. Illustration of Standard Penetration Test

21

APPENDIX - A

BOREHOLE LOCATION PLAN, GEOLOGICAL INFORMATION AND BOREHOLE DATA

· LOCATION PLAN

· BOREHOLE LOCATION PLAN

· AS-BUILT BOREHOLE LOCATIONS

· CROSS - SECTIONS

· LEGENDS FOR DIFFERENT SOIL AND ROCK TYPES

· BOREHOLE LOGS

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VALLEY ROAD

TAMPINES ROAD

HO

UG

AN

G A

VE

NU

E 1

SIMO

NR

OA

D

UPPER

SERANGOON

ROAD

FLORENCE CLO

SE

S C A L E : 1 : 2 0 0 0B O R E H O L E L O C A T I O N P L A N

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OLD ALLUVIUMKALLANG FORMATION

GEOLOGICAL CLASSIFICATION

SECTION: BH1 - BH2 - BH3 - BH4 & BH5

VERTICAL SCALE -

HORIZONTAL SCALE -

Drawn By:

Checked By:

Date:

Date:NOT TO SCALENOT TO SCALE

1:300

26

ECON GEOTECH PTE LTD

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29


30


31


32


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APPENDIX – B

LABORATORY TEST RESULTS

· SUMMARY OF LAB TEST RESULTS OF PHYSICAL AND MECHANICAL PROPERTIES OF SOIL SAMPLES

· DETAIL TEST RESULTS OF PHYSICAL AND MECHANICAL PROPERTIES OF SOIL SAMPLES

¨ Results of Moisture Content & Bulk/Dry Density

¨ Results of Sieve Tests

¨ Results of Atterberg Limit Tests

¨ Results of Triaxial (UU) Tests

¨ Results of Triaxial (CU) Tests

· CERTIFICATE OF ACCREDIATIONS

38

SOIL INVESTIGATION REPORT

Project : Soil Investigation Work At Tampines Road/Upper Serangoon Road Date : 19 August 2014

IMPORTANT:

DISCLAIMER NOTICE

The Authority shall not be held responsible in any way for the accuracy or completeness of

the soil investigation report and shall not be liable for any loss or damages suffered or

expenses incurred by any parties as a result of any use of or reliance on the information in

the said report.

The successful tenderer/purchaser is to conduct his own soil investigation for the purpose of

his planning and development of the Land Parcel.

urban redevelopment authority

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