Two identical specimens of soft saturated normally consolidated clay were consolidated to 150 kPa in a triaxial

Question:

Two identical specimens of soft saturated normally consolidated clay were consolidated to 150 kPa in a triaxial apparatus. One specimen was sheared drained, and the principal stress difference at failure was 300 kPa. The other specimen was sheared un-drained, and the principal stress difference at failure was 200 kPa. Determine

(a) ∅' and ∅ total;

(b) U f in the un-drained specimen;

(d) The theoretical angle of failure planes for both specimens.?