A level ground surface exists in an area where soil in the underlying stratum has a wet unit weight of 19 kN/m 3 . The vertical pressure at any depth represents the major principal stress. The...

A level ground surface exists in an area where soil in the underlying stratum has a wet unit weight of 19 kN/m³. The vertical pressure at any depth represents the major principal stress. The vertical pressure (stress) is the product of the soil unit weight and depth. The lateral pressure at a corresponding depth is 0.45 times the vertical pressure and represents the minor principal stress.

(a) Determine the principal stresses acting at a depth 4 m below the surface, and draw the Mohr’s circle for the condition.

(b) What is the maximum shear stress acting at this depth?