Calculation of Passive Pressure in Sand

Experimental investigations of passive earth pressures in sand show that current theoretical solutions overestimate failure loads and give incorrect stress distributions. Plasticity analysis has been used to examine the effects of changes in boundary friction and rotation preceding failure. Solutions have been developed to determine the magnitude of the scale effect due to the angle of shearing resistance of the sand varying with stress level in the failure zone. By assuming that the lower 30% of the wall does not reach plastic failure stresses, an assumption suggested by a recent experimental investigation, values of passive pressure coefficient Kp have been calculated, which agree well with experimental values over a wide range of sand densities.