week 3 tut - = 20., sat = 19kN/m3 Assume water table is at...

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Geomechnics 2 Civl 462 Tutorial Sheet-3 1. A strip footing is to be designed to support a dead load of 500 kN/m and an imposed load of 300 kN/m at a depth of 0.7 m in a gravelly sand. Characteristic values of the shear strength parameters are c’=0 and φ ′ = 40°. Determine the required width of the footing if a factor of safety of 3.0 against shear failure is specified and assuming that the water table may rise to foundation level. The unit weight of the sand above the water table is 17kN/m 3 and below the water table the saturated unit weight is 20kN/m 3 . 2. A strip footing 3 m wide buried 1.2 m below the surface caries a central vertical load of 150 kN/m of the footing. What is the factor of safety against failure if the load is applied : (a) Instantaneously (b) very slowly The soil is a clay with the following properties Cu=25kN/m2; φ u =0; c’=5kN/m2, φ
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Unformatted text preview: = 20., sat = 19kN/m3 Assume water table is at the ground surface and use Terzaghis bearing capacity theory for shallow foundation 3. A footing 2.5 x 2.5 m carries a pressure of 400kN/m 2 at a depth of 1 m in a sand. The saturated unit weight of the sand is 20 kN/m 3 and the unit weight above the water table is 17 kN/m 3 . The design shear strength parameters are c=0 and = 40. Determine the factor of safety with respect to shear failure for the following cases 1. the water table is 5 m below the ground level 2. the water table is 1 m below the ground level 4. A load of 425kN/m is carried on a strip footing 2 m wide at a depth of 1 m in a stiff clay of saturated unit weight 21 kN/m 3 , the water table being at ground level. Determine the factor of safety with respect to shear failure (a) when c u = 105kN/m 2 and u =0....
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This note was uploaded on 11/03/2009 for the course ENGG CIVL243 taught by Professor Zheeenling during the Spring '09 term at DeAnza College.

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