A consolidated undrained (CU) triaxial test was performed on a specimen of saturated over- consolidated clay with a cell pressure of 400 kPa and a back pressure of 150 kPa. At failure, the total vertical stress on the sample was was (1000+) kPa. Assuming c' = (25+) kPa and p = 28 for the sample, (a) Plot the effective stress and total stress Mohr circles at failure, and also the failure line on the same plot. (6 Marks) (b) Determine the total pore water pressure in the sample at failure. (4 Marks) (c) Calculate the effective normal stress and the shear stress on the failure plane. (4 Marks)