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?

Air enters a horizontal, constant-diameter heating duct operating at steady state at 290 k, 1 bar, with a volumetric flow rate of 0.25 m°/s, and exits at 325 k, 0.95 bar. the flow area is 0.04 m2. assuming the ideal gas model with k = 1.4 for the air, determine (a) the velocity at the inlet and exit, each in m/s, and (c) the rate of heat transfer, in kw flow rate, in kg/s, (b) the mass kg 0.3