On the development of a model of the thermo-mechanical-hydraulic behaviour of unsaturated soils

The development of a model of the thermo-mechanical-hydraulic behaviour of unsaturated soil is described. A step by step approach is adopted, taking as a starting point a potential-based model of coupled heat and moisture transfer. Extensions of this work to include the effect of air transfer and the deformation characteristics of the soil are presented. Constitutive relationships which accommodate non-linear elasticity, thermoelasticity and elasto-plasticity are considered. Numerical solutions of the various versions of the model are presented. Validation of the versions of the model, at their differing stages of development, is considered in turn and results presented in support of each case. The need for further, on-going research is also suggested, with a view towards resolving remaining problems of concern in safety assessment.