A retaining wall, 6 m high supports back fill with a horizontal surface and a water table at 2m below ground level. The soil is sandy soil and has a

unit weight of 17.5kN/m?, above the water table and 20 kN/m³ below, design angle of internal friction is ø'crit = 37°. The wall is 2.5 m embedded into the ground. The water table at the front of the wall is at 0.5 m below the ground level. Determine the total horizontal trust (active, passive and from the pore water pressure) on the back and front of the rough wall (tan 8 = 0.75 tan o' ). Use linear seepage approximation to calculate pore water pressure.