CONTENTS
Page
1. GeneralsG 4
2. Field Investigation WorkG 4
3. Laboratory Testing Work--- 5
4. Surface Soil Description-- 7
Appendix A
Borehole Location Plan 11
Soil Profile-- 15
Bore Logs--=---- 18
Appendix B
Quantity of Field Works and Laboratory Tests 28
Laboratory Test Summary-- 30
Result of Laboratory Testing Works 32
Appendix C
SPT Vs Depth--- 60
Calibration of SPT Hammer Energy Ratio ( Er )- 62
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1. General Cast Laboratories Pte Ltd was engaged by Urban Redevelopment Authority, Soil investigation Works at Fourth Avenue. The soil investigation works comprised drilling of (3) boreholes with associated undisturbed sampling, disturbed sampling and necessary in- situ testing as well as laboratory testing. The purpose of the investigation was to obtain geotechnical information on the subsoil conditions at the site. The field investigation for drilling of boreholes was conducted at 3 April 2017 to 15 April 2017. Laboratory tests were conducted on selected soil samples in Cast Laboratories Pte Ltd.
2. Field Investigation Work Trial pit by manually followed hand auger up to 3.0m depth was conducted at each borehole in order to avoid damage to underground utilities services. Bore holes with the nominal diameter of 100 mm were drilled using TOHO rotary drill rigs. 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 stabilize the borehole and wash out the cuttings to ground surface. Partial casing was used to stabilize the borehole side apart from using mud circulation. Thin-walled undisturbed push samples were collected from the soft to stiff cohesive soil layers by pushing a 76 mm-diameter thin-walled sampling tube into the soil by the static thrust of the drilling rig. Upon removal of the tube from the borehole, the tube was cleaned and both ends of the tube sealed with paraffin wax immediately. SPT's were being performed to determine the relative density or consistency of soils and to obtain soil samples for visual classification. A standard split barrel sampler of 50mm outer diameter was lowered to the bottom of the borehole on drill rods. The sampler was then driven 450mm into the soil by a 63.5kg self - tripping hammer free falling from a height of 760mm. The blow counts required to advance the final 300mm of a 450mm sampler drive was recorded on the borehole logs as SPT ‘N’ values. In dense strata where it was difficult to drive the sampler the full 450mm, the
4
penetration achieved beyond the initial 150mm seating drive with 100 blows of the hammer was recorded instead. After inspection, the recovered samples were placed in double polythene bags for soil identification.
3. Laboratory Testing Work The undisturbed samples were extruded from their sampling tubes, examined and visually classified. The laboratory testing work was set up to identify the soil strata adequately, and the strength and deformation properties of the subsurface soils for foundation design. All samples were examined by a soil lab technician and checked against the laboratory test results before the final description. Basically, the lab testing work is consisting of two main groups as below: (I) Classification Test • Moisture content and Bulk and Dry Density • Atterberg limits, Particle Size distribution by sieving
(II) Strength Tests • Uconsolidated-Undrained (UU) triaxial compression test --• Direct Shear Test
(I) Classification Test Moisture Content, Bulk and Dry Density 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. 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/m3, which is numerically the same as g/cm3.
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Atterberg Limits Test The Atterberg limits refer to arbitrarily defined boundaries between the liquid and plastic states (ie, liquid limit, WL) and between the plastic and brittle states (ie, plastic limit, WP), of fine grained soils. They are expressed in percentage water content. The range of water contents over which a soil behaves plastically is termed the Plastic Index and corresponds to the numerical difference between the liquid and plastic limit (ie, WL-WP). Tests to determine the Atterberg limits can be performed on soil samples of cohesive material. The soil is dried and then ground into separate grains using a mortar. The soil grains larger than 425m size are removed by sieving. The soil is then thoroughly mixed with different quantities of distilled water. Particle Size Distribution (Sieve Analysis) Particle size distribution is determined by means of sieving, hydrometer tests, or both. The percentage of weight of the various particle sizes in excess of 63m is determined by sieving through a set of standard sieves. When there is a considerable amount of particles smaller than 63m, the sieving is complemented by a hydrometer test in which the sample is mixed with water and stirred for about 15minutes. An additive prevents flocculation of the soil particles. After mixing, the density of the water-soil slurry is measured at fixed time intervals, and the particle size distribution of the sediment particles can be determined.
(II) Strength Tests Unconsolidated-Untrained (UU) Triaxial Compression Test This test is performed on undisturbed samples of cohesive soils. The test specimen - 38mm in diameter and 76mm in height - is prepared by trimming. A rubber membrane is placed around the specimen and a confining pressure is applied to the sample. During the axial loading of the specimen, the confining pressure is kept constant and drainage of pore water is not allowed. The test is continued until the specimen shears and a peak value is obtained, or until 20 percent strain has occurred. The results of the tests are presented as deviator stress versus axial strain. The undrained shear strength, defined as half the ultimate deviator stress, can be derived from these presentations and is reported to the nearest whole kPa.
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Direct Shear Test Direct Shear box test is performed to determine the shear strength of soil. A specimen is placed in a circular shear box which has two split rings to hold the sample and the contact between the two rings is horizontally around the mid-height of the sample. Porous plates are used to allow free drainage. A vertical force (N) is applied to the specimen through a loading plate and shear stress is gradually applied on a horizontal plane by casing the two halves of the box to move relative to each other, the shear force (T) being measured together with the corresponding shear displacement.
4. Subsurface Soil Description
The entire area under site investigation works is underlain by KALLANG FORMATION (Fluvial and Transitional) and BUKIT TIMAH GRANITE (Residual Soil, Completely Weathered, Highly Weathered, Moderately Weathered and Slightly Weathered) which in turn is overlain by unit of under FILL layer. The surficial unit is made up of FILL (made to ground by man). The following geological map shows the geological setting of the area.
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Geology and Site Vicinity Map of Soil Investigation Works At Fourth Avenue
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References 1. BS 1377:1990 – “Code of Practice for Laboratory Tests”, “Methods of Test for Civil Engineering Purposes”. 2. Geology of Singapore by PWD (1976) and DSTA (2009) 3. SS EN 1997 - 2 (2010), “Ground Investigation and Testing”. 4. BS EN 22475 - 1, “Drilling, Sampling and Ground Water Measurement”. 5. BS EN 22476 - 3, “The Calibration of SPT Hammer Energy Ratio (Er)”. 6. BS EN 14688, “Identification and Classification of Soil”. 7. BS EN 14689, “Identification and Classification of Rock”.
8 9 10
BH‐3 BH‐2
BH‐1
LEGEND BOREHOLE LOCATION PLAN OF FOURTH AVENUE Borehole
11 VANDA LINK
VANDA ROAD
VANDA DRIVE VANDA DRIVE
DUNEARN ROADTURF CLUB ROAD
BUKIT TIMAH ROAD Sixth Avenue MRT Station (DT7) Sixth Ave (Underground) Centre
ENG NEO AVENUE
VANDA ROAD JALAN NAGA SARI SIXTH AVENUE ANAMALAI
Guthrie MRT entrance/ exit structure SIXTH AVENUE House CANAL AVENUE FIFTH AVENUE LILY AVENUE
PUB Pipeline Reserve LAND FIFTH PARCEL AVE Second LEMON AVENUE Avenue SIXTH CONDO Junction AVE VILLE
FOURTH AVENUE
SIXTH AVENUE FIFTH AVENUE
THIRD AVENUE
SECOND AVENUE
THIRD AVENUE
FIRST AVENUE
L O C A T I O N P L A N S C A L E : 1 : 5 0 0 0
12 BUKIT TIMAH ROAD CANAL
DUNEARN ROAD
SIXTH AVENUE
FIFTH AVENUE
FOURTH AVENUE
FIFTH AVENUE
THIRD AVENUE
B O R E H O L E L O C A T I O N P L A N S C A L E : 1 : 2 0 0 0
13 14 Borehole Terminated at 34.33m
Borehole Terminated at 43.30m
BH-1 & BH-2 GEOLOGICAL CLASSIFICATION
KALLANG FORMATION OLD ALLUVIUM JURONG FORMATION BUKIT TIMAH GRANITE
VERTICAL SCALE - 1:400 Drawn By : Ng How Yong Date:24-Apr-2017 HORIZONTAL SCALE - NOT TO SCALE
URBAN REDEVELOPMENT AUTHORITY
SOIL INVESTIGATION WORKS AT FOURTH AVENUE
15 Borehole Terminated at 43.30m Borehole terminated at 46.32m
BH1 & BH-3
GEOLOGICAL CLASSIFICATION
KALLANG FORMATION OLD ALLUVIUM JURONG FORMATION BUKIT TIMAH GRANITE
VERTICAL SCALE - 1:400 Drawn By : Ng How Yong Date: 24-Apr-2017 HORIZONTAL SCALE - NOT TO SCALE
URBAN REDEVELOPMENT AUTHORITY
SOIL INVESTIGATION WORKS AT FOURTH AVENUE
16 17 Trial Pit(1.0 x 0.8 x 1.5)m Hand auger 1.5m to 3.0m Firm to stiff Reddish brown Slightly gravelly sandy SILT with concrete hardcore (FILL)
Soft Brown Slightly sandy SILT Residual Soil (BUKIT TIMAH GRANITE)
Stiff Yellowish brown mottled with white Slightly sandy SILT Residual Soil (BUKIT TIMAH GRANITE) Very stiff Yellowish brown mottled with white Slightly sandy SILT Residual Soil (BUKIT TIMAH GRANITE)
Very stiff Reddish brown mottled with white Slightly gravelly sandy SILT Residual Soil (BUKIT TIMAH GRANITE)
18 Very stiff Reddish brown mottled with white Slightly gravelly sandy SILT Residual Soil (BUKIT TIMAH GRANITE)
Hard Reddish brown mottled with white Slightly gravelly sandy SILT Residual Soil (BUKIT TIMAH GRANITE)
Hard Reddish brown mottled with white Slightly gravelly sandy SILT Completely Weathered (BUKIT TIMAH GRANITE)
Hard Yellowish brown mottled with white Slightly gravelly sandy SILT Completely Weathered (BUKIT TIMAH GRANITE)
19 Hard Yellowish brown mottled with white Slightly gravelly sandy SILT Completely Weathered (BUKIT TIMAH GRANITE)
Borehole terminated at 43.30m
20 Trial Pit( 1.0 x 0.8 x 1.5)m Hand auger 1.5m to 3.0m Stiff Reddish brown Sandy SILT with hardcore (FILL)
Very soft Dark grey Peaty CLAY Transitional (KALLANG FORMATION)
Loose Light grey Silty SAND Fluvial (KALLANG FORMATION)
Stiff Yellowish brown mottled with white Slightly gravelly sandy SILT Residual Soil (BUKIT TIMAH GRANITE)
Very stiff Yellowish brown mottled with red Slightly gravelly sandy SILT Residual Soil (BUKIT TIMAH GRANITE) Hard Reddish brown mottled with yellow Slightly gravelly sandy SILT Residual Soil (BUKIT TIMAH GRANITE)
21 Hard Reddish brown mottled with yellow Slightly gravelly sandy SILT Residual Soil (BUKIT TIMAH GRANITE)
Hard Reddish brown mottled with yellow Slightly gravelly silty SAND Completely Weathered (BUKIT TIMAH GRANITE)
Borehole terminated at 34.33m
22 Trial Pit( 1.0 x 0.8 x 1.5)m Hand auger 1.5m to 3.0m Firm Reddish brown Slightly gravelly sandy SILT (FILL)
Very soft Dark grey Peaty CLAY Transitional (KALLANG FORMATION)
Stiff Yellowish brown mottled with light grey Slightly gravelly slightly sandy SILT Residual Soil (BUKIT TIMAH GRANITE)
Very stiff Yellowish brown spotted with white Slightly gravelly slightly sandy SILT Residual Soil (BUKIT TIMAH GRANITE) Hard Yellowish brown spotted with white Slightly gravelly sandy SILT Residual Soil (BUKIT TIMAH GRANITE)
23 Very stiff Yellowish brown spotted with white Slightly sandy SILT Residual Soil (BUKIT TIMAH GRANITE)
Hard Yellowish brown spotted with white Slightly gravelly sandy SILT Residual Soil (BUKIT TIMAH GRANITE)
Hard Yellowish brown mottled with white Slightly gravelly sandy SILT Completely Weathered(BUKIT TIMAH GRANITE)
24 1
Hard Yellowish brown mottled with white Slightly gravelly sandy SILT Completely Weathered (BUKIT TIMAH GRANITE)
Borehole terminated at 46.32m
25 26 27 SOIL INVESTIGATION WORKS AT FOURTH AVENUE ROAD
QUANTITY OF FIELD WORKS AND LABORATORY TESTS
In Situ Test & Sampling Soil Drilling Work Soil Laboratory Test Test DS Undisturbed Sample Borehole No. Finished Total Rock MZ/Thick Starting Date Trial Pit Size Soil Drilling VST SPT TW PS Date Drilling Coring wall LL/PL UU CU Direct Shear Direct Bulk Density Consolidation Water Content (mxmxm) (m) (m) (m) Particle Density Grain Size (Sieve) Size Grain Grain Size (Hydro) Size Grain BH-1 04-Apr-17 07-Apr-17 (1.0 x 0.8 x 1.5) 43.30 43.30 0.00 - 14 2 0 0 2 2 0 0 1 1 1 0 0 1 BH-2 05-Apr-17 10-Apr-17 (1.0 x 0.8 x 1.5) 34.33 34.33 0.00 - 11 2 0 0 2 2 0 0 1 1 0 0 0 1 BH-3 10-Apr-17 13-Apr-17 (1.0 x 0.8 x 1.5) 46.32 46.32 0.00 - 15 2 0 0 2 2 0 0 1 1 0 0 0 1
TOTAL 123.94 123.94 0.00 0 40 6 0 0 6 6 0 0 3 3 1 0 0 3
Note:
1) Trial Pit ~ Hand Auger from GL-1.0, 1.5 to 3.0m 2) SPT = Standard Penetration Test 3)TW = Thin Wall Soil Sample , PS = Piston Soil Sample ,MZ= Mazier Sample 4) LL/PL = Atterberg Limits Test
28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 SPT Vs Depth ( BH-1 to BH-3)
SPT N Values
0 20406080100 0.00
10.00 BH1
20.00
Depth (m) BH2
30.00
BH3
40.00
50.00
Client : Urban Redevelopment Authority
Project : Soil Investigation Works at Fourth Avenue
Contractor : CAST Laboratories Pte.Ltd.
60 61 62 63 64 65 66 SOIL INVESTIGATION REPORT
Project : Soil Investigation Work At Fourth Avenue
Date : 4 May 2017
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.