(Solved):     ( b ) A slope with a given failure surface is shown in Figure Q.3 ( b ) . The unit ...

 

 

( b ) A slope with a given failure surface is shown in Figure Q.3 ( b ) . The unit weight of the soil both above and below the water table is 19 kN / m³ and the relevant shear strength parameters are c ' = 12 kN / m² and ' = 28 ° respectively . Assume there is no tension crack developed . Determine the factor of safety in terms of effective stress using Fellenius's method of slices for the given failure surface using 5 slices with dimensions given in Table Q.3 ( b ) when there is

i ) NO surcharge ; and ( ii ) a surcharge of 80 kN / m² acts on top of Slice No. 5 . [ The piezometric levels ( hw ) are the same as shown for both cases . ] ( 12 marks ) ( 8 marks )

(b) A slope with a given failure surface is shown in Figure Q.3(b). The unit weight of the soil both above and below the water table is \( 19 \mathrm{kN} / \mathrm{m}^{3} \) and the relevant shear strength parameters are \( \mathrm{c}^{\prime}=12 \mathrm{kN} / \mathrm{m}^{2} \) and \( \phi^{\prime}=28^{\circ} \) respectively. Assume there is no tension crack developed. Determine the factor of safety in terms of effective stress using Fellenius's method of slices for the given failure surface using 5 slices with dimensions given in Table \( \mathbf{Q . 3 ( b )} \) when there is (i) NO surcharge; and (12 marks) (ii) a surcharge of \( 80 \mathrm{kN} / \mathrm{m}^{2} \) acts on top of Slice No. 5 . \( (8 \) marks) [The piezometric levels ( \( h_{w} \) ) are the same as shown for both cases.] Figure Q.3(b): Cross Section of the proposed slope Tahle \( \cap 3(h) \). Slone dimensions and niezometric levels Table Q.3(b): Slope dimensions and piezometric levels