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Problem 2. A circular satellite tracking antenna foundation rests on a deposit of green marine clay of Eocene age (no embedment). The foundation is a reinforced concrete construction with a diameter of 5.25 meters and a thickness of 0.75 m. The groundwater at the site is almost at the ground surface. Undisturbed samples taken in a boring at the site are brought to a nearby lab, and testing determines the following parameters: Total unit weight = 15.7 kN/m; Degree of Saturation, S = 99.89% swelling index, Cs = 0.07; Virgin compression index, Cc = 0.63; coefficient of consolidation, cv = 1.55 cm?/min; Liquid limit LL = 64 %; plasticity index, PI = 33%; natural water content, w. = 52.5%; effective friction angle, d' = 30. (a) Evaluate the profile of total and effective vertical overburden stresses with depth within the zone of interest. (b) Using the given piezocone (CPTU) sounding, estimate the profile of P: (or op) and corresponding OCR in the clay. Note: Use the following relationship based on net cone tip resistance (qe): Op = (at - Ov)/3 (here, or = total vertical stress) CPT Sounding Results Depth Tip resistance, Side friction, Porewater (m) 9 (kPa) fs (kPa) pressure, uz (kPa) 0.00 0.00 0.00 0.00 0.50 118.75 7.65 50.60 1.00 135.25 7.79 62.70 1.50 150.02 8.31 74.00 2.00 168.30 8.93 86.90 2.50 182.81 8.79 98.10 3.00 200.98 9.27 110.90 3.50 215.67 10.36 122.20 4.00 233.06 10.20 134.70 4.50 235.06 10.81 140.10 5.00 267.11 11.46 159.40 5.50 282.28 11.17 170.90 6.00 300.07 11.56 183.50 6.50 308.77 11.78 192.00 7.00 332.60 12.30 207.50 7.50 347.41 13.78 218.80 8.00 368.35 14.17 232.90 8.50 380.06 14.32 242.80 9.00 393.16 14.22 253.40 9.50 409.24 14.60 265.30 10.00 426.07 15.62 277.50 4 (c) Obtain the undrained shear strength (su or C.) profile using the OCR with the following Critical State Soil Mechanics (CSSM) approach. Note: CSSM approach - = sino' - OCR4 (here, 4 = 1-C5/CC) (d) Determine the average undrained shear strength beneath the foundation (in the zone of concern). Calculate the allowable maximum ULS design load (consider permanent load only) using EC7. Assume no eccentricity and inclined loading. (e) Problem 2. A circular satellite tracking antenna foundation rests on a deposit of green marine clay of Eocene age (no embedment). The foundation is a reinforced concrete construction with a diameter of 5.25 meters and a thickness of 0.75 m. The groundwater at the site is almost at the ground surface. Undisturbed samples taken in a boring at the site are brought to a nearby lab, and testing determines the following parameters: Total unit weight = 15.7 kN/m; Degree of Saturation, S = 99.89% swelling index, Cs = 0.07; Virgin compression index, Cc = 0.63; coefficient of consolidation, cv = 1.55 cm?/min; Liquid limit LL = 64 %; plasticity index, PI = 33%; natural water content, w. = 52.5%; effective friction angle, d' = 30. (a) Evaluate the profile of total and effective vertical overburden stresses with depth within the zone of interest. (b) Using the given piezocone (CPTU) sounding, estimate the profile of P: (or op) and corresponding OCR in the clay. Note: Use the following relationship based on net cone tip resistance (qe): Op = (at - Ov)/3 (here, or = total vertical stress) CPT Sounding Results Depth Tip resistance, Side friction, Porewater (m) 9 (kPa) fs (kPa) pressure, uz (kPa) 0.00 0.00 0.00 0.00 0.50 118.75 7.65 50.60 1.00 135.25 7.79 62.70 1.50 150.02 8.31 74.00 2.00 168.30 8.93 86.90 2.50 182.81 8.79 98.10 3.00 200.98 9.27 110.90 3.50 215.67 10.36 122.20 4.00 233.06 10.20 134.70 4.50 235.06 10.81 140.10 5.00 267.11 11.46 159.40 5.50 282.28 11.17 170.90 6.00 300.07 11.56 183.50 6.50 308.77 11.78 192.00 7.00 332.60 12.30 207.50 7.50 347.41 13.78 218.80 8.00 368.35 14.17 232.90 8.50 380.06 14.32 242.80 9.00 393.16 14.22 253.40 9.50 409.24 14.60 265.30 10.00 426.07 15.62 277.50 4 (c) Obtain the undrained shear strength (su or C.) profile using the OCR with the following Critical State Soil Mechanics (CSSM) approach. Note: CSSM approach - = sino' - OCR4 (here, 4 = 1-C5/CC) (d) Determine the average undrained shear strength beneath the foundation (in the zone of concern). Calculate the allowable maximum ULS design load (consider permanent load only) using EC7. Assume no eccentricity and inclined loading. (e)

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