A rectangular footing of size 4m by 5m is founded at 2m below ground level in...

 

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A rectangular footing of size 4m by 5m is founded at 2m below ground level in a uniform deposit of saturated clay. The footing is designed to support a total vertical load of 8000 kN inclusive of the weight of the footing. The shear strength of the soil obtained from the respective laboratory tests are given below: Unconsolidated Undrained test: Consolidated Drained test: Cu 160 kN/m, = 0 = c = 6 kN/m, '= 32 The saturated unit weight of the soil ysat is 20 kN/m. Ground water table is assumed to be at the ground surface. The General Bearing Capacity equation will be adopted. (i) Determine the gross factor of safety of the foundation under long term situation. (ii) Also evaluate the gross factor of safety of the foundation under short term stability. ZAY 2 m 4 m 4m x 5m foundation G. L Ysat 20 kN/m Figure Q.4(a) (NTS) (b) A bearing capacity failure is defined as a foundation failure that occurs when the shear stresses in the soil exceed the shear strength of the soil. Besides the general shear failure, suggest other types of failure and briefly explain the mechanisms of the failure. A rectangular footing of size 4m by 5m is founded at 2m below ground level in a uniform deposit of saturated clay. The footing is designed to support a total vertical load of 8000 kN inclusive of the weight of the footing. The shear strength of the soil obtained from the respective laboratory tests are given below: Unconsolidated Undrained test: Consolidated Drained test: Cu 160 kN/m, = 0 = c = 6 kN/m, '= 32 The saturated unit weight of the soil ysat is 20 kN/m. Ground water table is assumed to be at the ground surface. The General Bearing Capacity equation will be adopted. (i) Determine the gross factor of safety of the foundation under long term situation. (ii) Also evaluate the gross factor of safety of the foundation under short term stability. ZAY 2 m 4 m 4m x 5m foundation G. L Ysat 20 kN/m Figure Q.4(a) (NTS) (b) A bearing capacity failure is defined as a foundation failure that occurs when the shear stresses in the soil exceed the shear strength of the soil. Besides the general shear failure, suggest other types of failure and briefly explain the mechanisms of the failure.