A time-dependent plasticity model for structured soils (TMS) simulating drained tertiary creep

Abstract

The model combines structure degradation of inviscid soils with viscous effects, on the premise that viscous volumetric strains increase structure, stiffness and strength, while plastic strains and viscous shear strains cause structure degradation, reducing the short-term strength to a user-controlled lower critical state strength at large plastic/viscous shear strains. If viscous strength reduction is large and occurs fast enough, the model can predict tertiary creep failure not only under undrained conditions, but also in drained stress-controlled tests (where most similar viscous models are tested) and in drained boundary value problems (where many viscous constitutive models fail to predict failure).