Q4. Three triaxial consolidated-drained (CD) tests were conducted on specimens of a saturated NC clay soil at different levels of confining stress. The applied deviator stresses at failure were recorded as below: Specimen Confining stress Deviator stress # 031 (01-03)1 (-) (kPa) (kPa) 1 69 121 2 3 138 207 238 373 a). Plot the Mohr's circles for the failure condition for all three specimens on the same plot. Provide sample calculations for Specimen 3 (01, radius, center). b). Draw the Mohr-Coulomb failure envelope and determine graphically the angle of internal friction, and the cohesion, c of the soil. c). Determine graphically for Specimen #3 (only), the normal and shear stresses on the failure plane at failure and the orientation of the failure plane. d). If another specimen of the same saturated clay is sheared under CD conditions at a confining stress of 300 kPa in a triaxial apparatus, what would be the expected deviator stress at failure? Show calculations to support your answer.