Question

A saturated soil sample under CU test was subjected to a confining pressure of 200 kPa with back pressure (pore pressure) of 50 kPa. What would be the value of pore pressure if the confining pressure was raised to 400 kPa without drainage? If the pore pressure parameter A is 0.5, determine the pore pressure if a deviatoric stress of 200 kPa was applied to the sample.