Mechanical constitutive framework for thermal effects on unsaturated soils

Research interest in the thermo-mechanical behaviour of unsaturated soils is growing as a result of an increasing number of geomechanical problems involving both thermal and suction effects. The underground waste disposal is one such critical problem. Until now, these two environmental loadings have often been considered independently This paper proposes a new unified thermo-mechanical framework for unsaturated soils based on thermo-hydro-mechanical (THM) experimental evidence on cohesive soils. The Bishop effective stress framework is adopted to represent the stress state in the soil in a unified fashion. This constitutive context based on the evolution of two key parameters (the preconsolidation pressure and the suction air-entry value) makes it possible to represent the main features of the thermo-mechanical behaviour of unsaturated soils.