Geotechnical Investigation Test Report

Transcription

1 Geotechnical Investigation Test Report Report No. htsc/rcd/ 3457 Dated: - 20/03/2010 Asphalt Standard Penetration Test as per IS IS 6403 Soil Job Card No Cement Client/Department M/S PDCOR Ltd., LIC Building, Bhawani Singh Road Ambedkar Circle, Jaipur (Rajsthan) Concrete Location of Site Pushkar, Ajmer (Rajasthan) Aggregates Date of Sampling 15 March 2010 Bricks Lime Date of Laboratory Testing 16 March 2010 Steel Tiles H. S. C. Hi-tech Scientific Corporation B / 11 / Automobile Nagar Delhi Bye pass Jaipur (Rajasthan) Telefax: Mobile: ashim@hscindia.in Website: 1

2 SOIL INVESTIGATION & TEST REPORT 1. INTRODUCTION:- The main function of a foundation is to distribute or transmit all loads coming over it to the soil or ground upon which it rests. The knowledge of the characteristics of underlying soil is therefore very essential for safe & economical design of foundations. The performance of supporting stratum depends upon the physical properties of soil type & shape of footing & structure, water table depth etc. 2. CLIENT:- The work of soil investigation for this project was awarded to Hi-tech Scientific Corporation, Jaipur by M/s PDCOR Ltd., LIC Building, Bhawani Singh Road, Ambedkar Circle, Jaipur (Rajasthan). 3. LOCATION & CHARACTERISTICS OF THE SITE:- The site for soil investigation is situated at Pushkar, Ajmer (Rajasthan) 4. SCOPE OF WORK:- Field investigation at the site are planned to determine the required characteristics of underlying soil to design the foundations of the proposed structure, the data obtained from these investigations have been analyzed to arrive at the required parameters, mainly the safe bearing capacity of the soil at various depth with respect to the existing ground level. In order to achieve the stated objectives, the stipulated scope of work included following Operations: (1) Transportation of the personnel, plant and equipment to the site of work and with drawing the same on completion of Work. (II) (III) (IV) (V) Drilling two boreholes of 100 mm diameter from the ground level to 6m or up to refusal strata. Conducting Standard Penetration Test in the two boreholes as per Indian standard specification (IS-2131). Extracting undisturbed soil samples and sealing, numbering and preserving them as per (IS-2132). Carrying out following necessary test on the soil samples. 2

3 Characteristics:- Sieve analysis Natural moisture content Bulk density Specific gravity Atterberg limits Determination of Shear Parameters (VI) Preparation and submission of detailed soil investigation report in duplicate. 5.0 INFORMATION ABOUT THE PROJECT:- This project included geotechnical investigations up to 6m depth or refusal strata for BH-1 and BH-2 as decided by the client. 6.0 FIELD INVESTIGATION (STANDARD PENETRATION TEST-SPT):- The subsurface investigation in the field involves three basic operations: Drilling. Sampling. Conducting the required field test. This is followed by operation in the laboratory for conducting other prescribed tests. 6.1 DRILLING BOREHOLES:- Two boreholes (BH-1 and BH-2) of diameter 100mm were drilled with the help of a posthole auger. The auger was pressed into the soil and twisted. Extension rods were connected to auger to increase the reach of auger inside the borehole, up to the decided depth. Any loose soil was carefully removed from the bottom of the borehole so that the penetration test may be performed on natural grounds. 6.2 STANDARD PENETRATION TEST:- The standard penetration test was conducted in the two boreholes following the standard Procedure as per Indian Standard: IS , which specifies the procedure for conducting SPT for soil. This test is carried out using the standard split spoon sampler to measure the number of blows called N value. 3

4 7.0 LABORATORY TESTS:- In the laboratory, the samples were extracted out carefully from the undisturbed sample tubes, which were collected from the test bore hole. Undisturbed samples were than used to carry out the following tests:- Determination of dry density. Determination of Bulk density. Determination natural moisture content. Determination of Shear Parameters Other tests conducted on disturbed samples are: Sieve analysis. Atterberg limits. Specific gravity test. All test were conducted in accordance with the procedure laid down in Indian Standard IS: 2720, results obtained are presented in Table 2 and Table-3 bearing capacity results based on IS: Part I 1976 are presented in Table-4 and Table RESULTS:- The safe Bearing capacity at depth is presented in Table-1 and is based on settlement criteria and local shear criteria the tested values and the minimum values for the two bore holes. Table no 1: Safe Bearing Capacity minimum of two bore holes Depth Meter Safe Bearing Capacity Recommended Settlement Criteria t/m² Local Shear Criteria Safe Bearing t/m² Capacity t/ m² Refusal strata encountered at 4.00m in BH-1 & 3.75m depth in BH Limited to 15 T/m² for fine sand. 4

5 9.0 ANALYSIS OF TEST RESULTS:- The field investigation and laboratory tests conducted over the soil revealed the following conclusions: RESULTS OF LABORATORY TEST Table 2 Soil Properties for bore hole-1 S.No. Soil Property Depth m Clay & Silt (%) Remarks 2. Fine Sand (%) Medium Sand (%) Coarse Sand (%) Gravel and Boulder (%) Liquid Limit (%) Plastic Limit (%) Plasticity Index (%) Non PI Non PI Non PI 9. Sp. Gravity Refusal strata encountered at 4.00m depth Angle of Internal Friction Ø 11. Av. Bulk Density (gm/cc)

6 Table 3 Soil Properties for bore hole-2 S.No. Soil Property Depth m Clay & Silt (%) Remarks 2. Fine Sand (%) Medium Sand (%) Coarse Sand (%) Gravel and Boulder (%) Liquid Limit (%) Plastic Limit (%) Plasticity Index (%) Non PI Non PI Non PI 9. Sp. Gravity Refusal strata encountered at 3.75m depth Angle of Internal Friction Ø 11. Av. Bulk Density (gm/cc) Bulk density Bore Hole 1 Bore Hole gm/cc gm/cc 6

7 TABLE NO-4: Safe Bearing Capacity local Shear Criteria B.H. BH- 1 BH- 2 Depth (m) Width (m) Av Bulk Density gm/cm³ Cohesion t / m² Angle of repose Ø Ø Nc Nq Nr Qnf(t/m²) Qns(t/m²) Refusal strata encountered at 4.00m depth in BH Refusal strata encountered at 3.75m depth in BH-2. Qs Note: ø Angel of Repose Nc- Nq- Nr- Bearing Capacity Factor W - Water Table Correction Factor Qnf-Net Ultimate Bearing Capacity Qns-Net safe Bearing Capacity Qs- Safe Bearing Capacity Table No 5: Safe Bearing Capacity 25mm Settlement Criteria B.H. 1 2 Depth Bulk density N Corrected Qns t/m² Qs t/m² (m) gm/cc N Refusal strata encountered at 4.00m depth in BH Refusal strata encountered at 3.75m depth in BH

8 BORE HOLE NO 1 Soil stratum from ground level to refusal strata at 4.0m shows fine sand with quantity of silt varying from 5.50 to 6.50 %. Based on N values it was concluded that soil was loose up to 1.5m depth and of medium density at 3.0m depth. Water table was not encountered during borehole drilling. BORE HOLE NO 2 Soil stratum from ground level to refusal strata at 3.75m shows fine sand with quantity of silt varying from 4.43 to 6.67%. Based on N values it was concluded that soil was loose up to 1.5m depth and of medium density at 3.0m depth. Water table was not encountered during borehole drilling ALLOWABLE BEARING CAPACITY:- Considering the proposed structure and taking in to account the N value an allowable settlement of 25 mm has been adopted for evaluating the net allowable bearing capacity, based on the settlement criterion. Average shear strength parameters have been used for calculating safe bearing capacity from local shear failure criterion. Lower of the two values obtained from settlement and local shear criteria is used in arriving at net allowable bearing capacity of the soil, as shown in Table -1 8

9 11.0 CONCLUSIONS:- The soil at this site is fine sand up to refusal strata it is classified as sandy soil. SPT N Values reveals that soil stratum is loose from ground level to 1.5m and of medium density at 3.0m. No rock was observed up to refusal strata in BH-1 & BH-2. No water table was encountered up to refusal strata in BH-1 & BH-2. Soil is suitable for strip footing for load bearing wall construction. For column and beam framed structure individual rectangular or square footing or raft footing can be adopted. Remarks: 1. The result is of sample of soil collected through SPT test. 2. The sample will be preserved in our laboratory for a period of fifteen day s only. 3. This report can not be produced for legal purposes. 4. Subject to Jaipur (Rajasthan) Jurisdiction only. 5. This report should not be treated as the endorsement of the sample submitted for testing. Checked and approved Hi-tech Scientific Corporation Dr. R. P. Kashyap M.E., Ph. D, MISTE, MIAH, MIWRS Executive Director 9