Effect of excavation on the thermo-hydro-mechanical behaviour of a geological barrier

This paper presents a fully coupled thermo-hydro-mechanical (THM) formulation for an unsaturated soil. All significant coupled interactions between the different components involved in an unsaturated porous medium subjected to heating are considered. The THM model has been integrated into the Code_Aster by Gatmiri at CERMES and has been used in to investigate the THM behaviour of nuclear waste repositories. The effects of repository excavation on the hydraulic and mechanical behaviour of the rock before waste disposal have been investigated, as well as the thermo-hydro-mechanical behaviour of the geological barrier after waste emplacement. Analyses have shown that modelling of the excavation stage is of great importance due to the considerable effects of the THM processes on the hydraulic and mechanical properties of the surrounding media.