Coupled computations for an elastic-perfectly plastic soil using adaptive mesh refinement

Abstract

An adaptive mesh refinement algorithm has been developed for non-linear computations in geomechanics, based on a smoothed stress-strain finite element formulation. This uses estimates of error in the incremental shear strain invariant to guide the regeneration of unstructured meshes at regular intervals during loading. Following each mesh-update, no re-analysis of previous increments with the new mesh is necessary. Algorithm performance has been investigated by analysing a passive earth pressure problem using a linear elastic-perfectly plastic Mohr-Coulomb soil model. Perfectly drained behaviour has been considered, as have partially drained situations using hydromechanical coupling, while undrained behaviour has been approximated using time steps close to zero. In all cases, mesh adaptivity has been successful in capturing regions of high strain gradient. The results have been compared with analytical solutions. Accurate computations of limit load and shear band orientation have been obtained for a wide range of material dilation angles. Copyright (C) 2000 John Wiley and Sons, Ltd.