A12-ft tall concrete wall with a vertical back is to be backfilled with a clayey sand that has a unit weight of 126 pcf, an effective cohesion of 500 psf, and an effective angle of 30 degrees. the ground behind the wall will be inclined at a slope of 2 horizontal to 1 vertical. compute the normal (e. g., horizontal) and shear (e. g., vertical) forces acting on the back of the wall. assume the wall moves sufficiently to develop the active conditions in the soil.