INSTRUCTION: Select the best answer to each of the following questions. Mark only one answer for each item by shading the box corresponding to the letter of your choice on the answer sheet provided. STRICTLY NO ERASURES ALLOWED. Use pencil no. 2 only DO NOT WRITE ANYTHING ON THIS PAPER. DO NOT FOLD OR MUTILATE. Situation: Assume a buried stratum of clay 1.83 m thick will be subjected to a stress increase of 33.6 KPa at the center of clay. The magnitude of the pre-construction soil overburden pressure is 48 KPa at the center of the clay layer. A laboratory compression test indicates that the clay has a pre-consolidation pressure of 72 KPa. Compression index is 0.3 and the value of swell index is 0.05. Void ratio of clay is 1.5. 1. Compute the settlement due to primary compression of clay. A. 16.5smm B. 17.6mm C. 18.4mm D. 19.8mm 2. If full consolidation settlement, primary compression settlement requires approximately 8 years, compute the settlement due to secondary compression of clay over a period of 20 years’ timespan. Assume secondary compression index is 0.008. Situation: A square footing has a dimension of 1.3m by 1.3m with its bottom 0.9m below the ground surface. The ground water table is located at a depth of 1.2m below the ground surface. Assume local shear failure. Use: Nc=37.16 Nq=22.46 Nɣ=19.30 ɣ=17.6 KN/m3c=12.2 kPa, Ø=30° Ɣsat=19.7 KN/m33. Compute the ultimate bearing capacity of the soil beneath the column. 4. Compute the allowable load that the footing can carry based on soil bearing capacity using FS=2.7. Situation: A 300 mm diameter test well penetrates 27 m. below the static water table. After 24 hours of pumping at 69 liters/sec. The water level in an observation well at a distance of 98 m. from the test well is lowered 0.56 m. and the other observation well at a distance of 34.5 m. from the test well, the drawdown is 1.10 m. 5. What is the rate of flow in m3/day? A. 6591.6 m3/day C. 5691.6 m3/day B. 6691.5 m3/day D. 5961.6 m3/day 6. Compute the coefficients of permeability of the aquifer in m/day. 7. Compute the transmissibility of the aquifer in m2/day. Situation: The soil has a specific gravity of 2.6 and porosity of 0.35. 8. Determine the dry unit weight.
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- Fall '18
- Prof Robles