Large-deformation geomechanical problems studied by a shear-transformation-zone model using the material point method

摘要

A non-equilibrium statistical thermodynamics-based framework for describing elasto-viscoplastic deformations in amorphous materials termed shear-transformation-zone (STZ) theory has been implemented in the material point method (MPM) and applied to the modeling of large-deformation geomechanical problems. Plane strain biaxial shear tests with different loading rates were first performed using the model to emphasize its ratedependency and to compare its performance with that of a mu(I) rheological model. The model was then utilized to simulate three classical large-deformation geomechanical problems, namely, the granular column collapse, the footing settling on a soft ground, and the soil-pipe interaction. It has been shown from this study that the STZ theory is promising in modeling rate-dependent viscoplastic behaviors of geomaterials, as well as solid-fluid phase transition and strain localization.