(Solved): Question 2 (20 Marks) A sample of a soft clay is to be tested in a conventional triaxial apparatus ...

Question 2 (20 Marks) A sample of a soft clay is to be tested in a conventional triaxial apparatus under undrained conditions, i.e. the so-called CU test. The sample is firstly isotropically consolidated under a cell pressure of 250 kPa and then allowed to swell back to a mean effective stress of 175 kPa. The soil parameters are ? = 0.15, x = 0.04, pcs = 26.7°, v' = 0.3, and ? = 1.08. a) Calculate initial yield stresses p'y, and qy [5 marks] b) Calculate failure stresses p', and qf, and [5 marks] c) Determine total deviatoric strains and the excess porewater pressure for a decrease of mean stresses of 1.5 kPa. [10 marks] Continued...