Thermo-Hydro-Mechanically Coupled Finite Element Analysis of Cohesive Soil using an Elasto-Viscoplastic Model

摘要

It is well known that viscous behavior of water-saturated clay depends on temperature variation as well as strain rate [1-2]. In addition, the conservation of energy during deformation should be considered since the plastic stress power changes the temperature of soil. In this paper, a thermo-hydro-mechanically coupled finite element method using an elasto-thermo-viscoplastic constitutive model for clay is newly developed based on Biot's type of multi-phase mixture theory, in which updated Lagrangian method is adopted. The elasto-thermo-viscoplastic model for soil can describe strain-rate dependency, temperature dependency, and softening behavior due to degradation of microstructure [3]. Firstly, a series of strain localization analysis under undrained plane strain conditions is conducted, in order to investigate the effects of temperature changes induced by the plastic stress power, on the strain localization behavior of clay modeled as a thermo-viscoplastic material. Secondly, thermal consolidation mainly due to heat-generated pore water pressure is simulated. It is found that the proposed analysis method can successfully simulate the temperature-dependent behavior of clay and that the temperature variation significantly affects the deformation behaviors of clay.