Pseudo-dynamic lateral earth pressures on rigid walls with varying cohesive-frictional backfill

Abstract

This study provides a procedure for assessing the seismic active and passive earth pressure acting on a rigid retaining wall, using the discretization-based kinematic analysis. Such a procedure is capable of considering varying soil properties of the backfill that widely exist in engineering practice owing to the nature of their origins and deposition, which otherwise would be difficult to be considered in conventional upper bound analysis. This is achieved by discretizing the backfill into finite elements by generating a coherent kinematically admissible failure mechanism. The current methodology (modified pseudo-dynamic approach) computes the time- and spatial effects of seismic acceleration through the inclusion of primary and shear waves. External and internal rates of work are calculated through summation of the elementary rates of work. Based on the work rate balance equation, upper bound formulations of active and passive earth pressures (coefficients) are derived in a pseudo-dynamic manner, with the specific kinematic solutions obtained with an optimization procedure. The active (passive) earth pressure coefficient undergoes a decrement (increment) with increasing soil cohesion and friction angle of the backfill, wall adhesion and friction, and shear wave velocity within certain range; and vice versa for the seismic acceleration’s effect.