Numerical Investigation of Gravity Wall-Granular Soil Interaction

Abstract

The active earth pressure developing in granular backfills is directly related to the internal friction angle. It is well known that the internal friction angle is a function of the level of mean effective stress and the level of shear strain in the retained soil. Both these variable change as the wall moves away from the backfill due to the compliance of the foundation soil. In this paper, simulations of the response of the wall-foundation-backfill system are performed using the finite element method in order to study the interaction between wall movement and active earth pressure. The granular soil is modeled using a bounding surface plasticity constitutive model for sands based on critical state soil mechanics. The finite element analyses show that the wall system reaches a minimum active stress state associated with a peak soil friction angle at wall crest displacement less than 0.5% of the wall height, relevant to a serviceability limit state rather than an ultimate limit state. By the time the ULS is reached the friction angle mobilized in parts of the retained soil mass has approached the critical state friction angle value due to the intense shear straining.