Study on the initiation of strain localization in soils by 3d non-coaxial plasticity

Abstract

The strain localization in soil under plane strain and true triaxial conditions were predicted by bifurcation analysis on the non-coaxial plasticity. By using an elliptical shape function to modify the Mohr-Coulomb failure criterion, a 3D non-coaxial non-associated elasto-plasticity model was proposed by adding a non-coaxial plasticity flow rule. Comparing to the experiments, bifurcation analysis on the non-coaxial model gives out better prediction than the coaxial models. Strain localization occurs at the hardening regime of the soil under plane strain condition, the influence of confining stress on the strain localization could be described by non-coaxial model rightly. The prediction of true triaxial tests showed the non-coaxial model reflects the influence of the intermediate stress ratio on strain localization well.