A specimen of sand is tested in direct simple shear. The stress conditions are shown. Initial conditions: σ v = 3.12 kg/cm2, Ko = 0.5 At failure: σ v = 3.12 kg/cm=, t hv = 1.80 kg/cm2

(a) Draw the Mohr circles for both initial and final stress conditions.

(b) Show clearly the locations of the poles of these circles.

(c) Determine the magnitude and orientation of the principal stresses at failure.

(d) What is the orientation of the failure plane?

(e) If the shear strain at failure is 10° as shown in the figure, what are the stresses and on the sides of the specimen at failure?