The effective stress parameters for a fully saturated clay are known to be c′=15 kn/m2 and φ′=29°. in an unconsolidated-undrained triaxial test on a specimen of the same clay the all-round pressure was 250 kn/m2 and the principal stress difference at failure 134 kn/m2. what was the value of pore water pressure in this specimen at failure?

Areheat rankine cycle operates with water as the working fluid. steam enters the first turbine at 8 mpa and 450°c and exits at 0.8 mpa. it is then reheated to 400°c before entering the second turbine, where it exits at 10 kpa. if the amount of work into the pump is 8.04 kj/kg and the net work per cycle produced is 1410.25 kj/kg, determine the thermal efficiency of the cycle.