Constitutive Modelling of Coupled Thermo-Hydro-Mechanical Behaviour in Unsaturated Soils

摘要

A thermo-hydro-mechanical constitutive model for unsaturated soils is proposed in this paper based on the existing models. The thermal softening phenomenon, i.e. decreases in value of the pre-consolidation pressure and in critical value of the suction of the SI (Suction Increasing) curve with heating process, are quantitatively modelled by using the experimental data and previous work [1-3]. The thermal yield behavior is also described in the present model [4]. A backward Euler return mapping procedure [5] in order to deal with non-smooth multi-surface plasticity is implemented in the finite element code CONVILAG. The comparisons of the results obtained from the numerical modelling of the constitutive behavior with existing experimental results show that the present model can simulate the thermo-hydro-mechanical behavior in unsaturated soils with satisfaction. Some other numerical results given in the paper also validate the versatility and applicability of the present constitutive model. The model has been extended to include the influences of chemo-mechanical effects, such as chemical softening [6] and cohesion change with respect to contaminant concentration. The coupled THMC constitutive model with it numerical modelling for unsaturated soils, as one of the important job, is performed in our research team.