Annexures of Form-1
Total Page：16
File Type：pdf, Size：1020Kb
ANNEXURES OF FORM-1 Annexure -7: Location of Project Site Annexures of Form – 1 “Turquoise II & IV” Page viii FINAL REPORT GEOTECHNICAL/SUB-SOIL INVESTIGATION AND RECOMMENDATION WORK FOR PROPOSED CONSTRUCTION OF BUILDING (G+10+) AT SURVEY NO: 308/3, FINAL PLOT NO: 10/3, T.P. SCHEME NO: 86, OPPOSITE APPLE WOODS, SHANTIPURA, TAL: SANAND, DIST.: AHMEDABAD, GUJARAT STATE. JOB NO. : MK/35/06-13 MONTH & YEAR: JUNE-2013 FORWARDED TO, GOYAL & COMPANY, 15FT FLOOR, COMMERCE HOUSE –IV, PRAHALADNAGAR, AHMEDABAD. M. K. SOIL TESTING LABORATORY BHARTI HOUSE, GROUND FLOOR, OPP. GRAND BHAGWATI HOTEL, NR. AVALON HOTEL, AND JAHNVI BUNGALOWS, OFF. S. G. HIGHWAY, BODAKDEV, AHMEDABAD – 380 054, PHONE NO.: +91-79-2682 0940, 2682 60860, 9624097903 EMAIL : [email protected], [email protected] Job No: MK/35/06-13 M. K. Soil Testing Laboratory, Ahmedabad – 54 CONTENTS SR. CHAPTER PAGE NO. NO. 1. Introduction. 01 2. Field Work. 01 3. Sub Soil Stratification 03 4. Discussion On Field And Laboratory Test Results 03 5. Typical Calculation of Safe Bearing Capacity 04 6. Summary 07 7. Recommendation 08 8. 1) Tables… 01-02 2) Drawings… 01-03 0 Job No: MK/35/06-13 M. K. Soil Testing Laboratory, Ahmedabad – 54 1.0 INTRODUCTION Goyal & Company, Ahmedabad proposes Geotechnical Investigation work for construction of Building (G+10+) at Survey No: 308/3, Final Plot No: 10/3, T.P. Scheme No: 86, Opposite Apple woods, Shantipura, Tal: Sanand, Dist.: Ahmedabad, Gujarat State. The object of the sub soil exploration was (i) To determine the probable sub surface conditions such as stratification, denseness or hardness of the strata, position of ground water table etc., and, (ii) To give probable range of safe bearing capacity for the structure. 2.0 FIELD WORK 2.1 Boring One borehole of 150mm diameter is to be drilled upto the depth of 12.00m depth below existing ground level (EGL). The work was in general accordance with IS: 1892 – 1979. The work was in general accordance with IS: 1892 – 1979. The borehole is located as shown in location plan shown as MK/35/06-13LP. 2.1.1 Disturbed Samples Disturbed representative samples were collected, logged, labelled and placed in polythene bags. 2.1.2 Undisturbed Samples Undisturbed soil samples are collected in 100mm diameter thin walled sampler (Shelby tube) from borehole. The sampler used for the sampling had smooth surface and appropriate area ratio and cutting edge angle thereby minimizing disturbance of soil during sampling. 1 Job No: MK/35/06-13 M. K. Soil Testing Laboratory, Ahmedabad – 54 2.1.3 Ground Water Table: Water table was encountered in the borehole at 7.25m depth below EGL, investigated during the sub surface investigation carried out in the month of (June - 2013) 2.1.4 Method of Sampling Sampler is coupled together with a sampler head to form a sampling assembly. The sampler head provide a non-flexible connection between the sampling tube and the drill rods. Vent holes are provided in the sampler head to allow escape of water from the top of sampler tube during penetration. The sampling tubes are made free from dust and rust. Coating of oil is applied on both sides to obtain the undisturbed samples in best possible manner. The sampler is then lowered inside the bore hole on a string of rods and driven to a pre-determined level. On completion of driving the sampler is first rotated within the borehole to shear the soil sample at bottom and then pulled out. Upon removal of the sampling tubes, the length of sample in the tube is recorded. The disturbed material in the upper end of the tube, if any, is completely removed before sealing. The soil at the lower end of the tube is trimmed to a distance of about 10 to 20 mm. After cleaning and inserting an impervious disc at each end, both ends are sealed. The empty space in the sampler, if any, is filled with the moist soil, and the ends covered with tight wrapper. The identification mark is then made on each sample. 2.2 Standard Penetration Test The standard penetration tests are conducted in each bore as per IS: 2131: 1981 (Reaffirmed 1987). The split spoon sampler resting on the bottom of bore hole is allowed to sink under its own weight, then the split spoon sampler is seated 15 cm with the blows of hammer falling through 750mm. The driving assembly consists of a driving head and a 63.5 kg weight. It is ensured that the energy of the falling weight is not reduced by friction between the drive weight and the guides or between ropes. 2 Job No: MK/35/06-13 M. K. Soil Testing Laboratory, Ahmedabad – 54 The rods to which the sampler is attached for driving are straight, tightly coupled and straight in alignment. Thereafter the split spoon sampler is further driven by 30cm. The number of blows required to drive each 15cm penetration is recorded. The first 15cm of drive considered as seating drive. The total blows required for the second and third 15cm penetration is termed as a penetration resistance - N value. The N- values for each bore hole are given in bore log attached in drawings. 3.0 SUB SOIL STRATIFICATION Field and laboratory test data reveal the general stratification as under : 3.1 Borehole: BH-1 Layer No.: 1 This layer from 0.0m to 3.50m is observed to consist of blackish brown to yellowish brown medium stiff to stiff silty clay having low plasticity (CL). Layer No.: 2 This layer from 3.50m to 12.00m is observed to consist of yellowish brown medium dense to dense non plastic silty sand (SM). 4.0 DISCUSSION ON FIELD AND LABORATORY TEST RESULTS: 4.1 Field Test SPT-N value tests are carried out in the borehole. The depth wise variation in SPT-N value is shown in bore log. The observed and corrected SPT values are given in table 1 of report. 4.2 Laboratory Test Laboratory test results for various soil samples as obtained from all the boreholes are shown in result sheets attached as table: 3 and Drawing no. MK/35/06-13DBH end of the report. 3 Job No: MK/35/06-13 M. K. Soil Testing Laboratory, Ahmedabad – 54 5.0 TYPICAL CALCULATIONS FOR SAFE BEARING CAPACITY: 5.1. Assumption / Data: i. Type of foundation considered : Square foundation. ii. Total Permissible settlement : 50mm for footing (Ref.: IS: 1904-1986) iii. Depth of foundation below GL : 4.50m iv. Depth of foundation below basement : 1.50m v. Size of foundation : 2.00m X 2.00m vi. Water Table : At 7.25m depth 5.2 Bearing Pressure Based on C & Values :- (Shear Criterion) For computing bearing capacity at 4.50m depth below GL following parameters are adopted. Cu = 0.0 Kg/cm2 = 30 (Considering mixed shear failure) The ultimate net bearing capacity for squarer foundation for mixed shear failure is given by equation Qnd = 2/3 C Nc Sc dc ic + q (Nq-1) sq dq iq + 0.5 B SD Nr Sr dr ir .............................(i) 4 Job No: MK/35/06-13 M. K. Soil Testing Laboratory, Ahmedabad – 54 Where, Qnd = Net ultimate bearing capacity of foundation. C = Cohesion = 0.00 Kg/cm2 DD = Dry density at foundation level = 0.00161 Kg/cm3 D = Effective Depth of foundation = 150 cm (below basement) B = Width of foundation = 200 cm q = Total surcharge at the base level of foundation. = 0.00161 x 150 = 0.24 Kg/cm2 Sc, Sq, Sr are shape factor for square footing. Sc = 1.30, Sq = 1.20, Sr = 0.80 dc, dq, dr, are depth factors, (Assuming that overburden soil is not compacted properly) dc = 1.0, dq = 1.0, dr = 1.0 ic, iq, ir are inclination factors. ic = iq = ir = 1.0 (Since load is vertical) Adopting Nc, Nq, Nr factors as per IS: 6403 as below : For = 30 and mixed shear failure Nc = 23.83, Nq = 13.42, Nr = 15.29 Qnd = [2/3 x 0.0 x 23.83 x 1.3 x 1.0 x 1.0] + [0.24 x (13.42 - 1) x 1.2 x 1.0 x 1.0] + [0.5 x 200 x 0.00161 x 15.29 x 0.8 x 1.0 x 1.0] = 0.00 + 3.57 + 1.96 = 5.53 Kg/cm2 5 Job No: MK/35/06-13 M. K. Soil Testing Laboratory, Ahmedabad – 54 Where, Qnd is net ultimate bearing capacity, Adopting factor of safety as 3.0 Qnd 5.53 qs = ------------ = ------------ FS 3.0 = 1.84 Kg/cm2 = 18.40 t/m2 say 18 t/m2. 5.3 Bearing Pressure Based on Settlement Criterion: (SPT Results) N = Average corrected N-value at 4.50m depth = 20 Using IS: 8009 - 1976 : (Part-1) for width = 2.00m. Settlement for load intensity of 10 t/m2 = 15 mm. Hence, for 50mm permissible settlement, 50 x 10 Probable Load intensity foundation = ------------ 15 = 33.33 t/m2. Hence, recommended SBC is 18 t/m2. 6 Job No: MK/35/06-13 M. K. Soil Testing Laboratory, Ahmedabad – 54 6.0 SUMMARY: Summary of Allowable Bearing Capacity Type & Size of Depth Depth NET SAFE BEARING CAPACITY Recommended Footing Below Below Shear Criterion Settlement Criterion Net Safe Ground Basement C & Value SPT results Bearing Level Level (t/m2) (t/m2) Capacity (m) (m) (t/m2) Square footing 4.50 1.50 18 33 18 2.00 x 2.00m 5.00 2.00 22 33 20 Square footing 4.50 1.50 21 30 20 3.00m x 3.00m 5.00 2.00 26 30 25 Square footing 4.50 1.50 25 29 25 4.00m x 4.00m 5.00 2.00 29 29 25 7 Job No: MK/35/06-13 M.