A soil deposit exists with a level ground surface. The saturated unit weight of the soil is 125 pcf, and the water table is at the ground surface. (a) Determine the principal stresses acting at a...

A soil deposit exists with a level ground surface. The saturated unit weight of the soil is 125 pcf, and the water table is at the ground surface.

(a) Determine the principal stresses acting at a depth 15 ft below the ground surface that results from the effective (submerged) soil weight if the lateral pressure is 0.45 times the vertical pressure. (Recall that the subsurface vertical and horizontal pressures or stresses are the principal stresses when the site surface is horizontal.)

(b) What is the magnitude of the maximum shear stress relating to the effective stresses at this depth?