Propagation of Localization Instability Under Active and Passive Loading

Abstract

The mechanical response of a solid continuum changes drastically as the deformation evolves from a diffuse state to a highly localized state. For this reason the subject of strain localization has received much research attention lately. This paper investigates the impact of strain localization in the form of strong discontinuity, or displacement jump, on the limit strengths of retaining walls supporting an elastoplastic backfill. The analysis focuses on the propagation of strong instability in active and passive loading using a recently developed strong discontinuity finite element model where the elements are enhanced to accommodate the presence of displacement jumps. Specifically, the analysis applies to dilative frictional material that is susceptible to shear banding. For the retaining wall problem, strong instability is shown to initiate at the ground surface and propagate downward at an angle that depends on the state of stress at the onset of localization.