The failure stresses and excess pore water pressures for three samples of a loose sand in CU tests are given below.
(a) Plot Mohr's circle of effective stress from these data.
(b) Determine the friction angle for each test.
(c) If the sand were to be subjected to a vertical effective stress of 300 kPa, what magnitude of horizontal effective stress would cause failure?
(d) Determine the inclination of (1) the failure plane and (2) the plane of maximum shear stress to the horizontal plane for Test
2.
(e) Determine the failure stresses for Test 1.
(f) Is the failure shear stress the maximum shear stress? Give reasons.