Fully coupled thermo-hydro-mechanical model with oversaturation and its validation to experimental data from FEBEX experiment

Abstract

The paper is devoted to the formulation of a mathematical model which enables analysis of coupled thermo-hydro-mechanical (THM) processes with a special focus on processes in bentonite and bentonite-based sealing barriers which are component of designs of deep geological repositories for a high-level radioactive waste including the spent nuclear fuel. Such modelling is important as the analysis of coupled THM processes in the near field is crucial for the understanding of the long-term behaviour of the barriers. The developed model uses generally available data from standard tests but attempts to incorporate special characteristics of the bentonite behaviour, let us mention the oversaturation, swelling and strong couplings of the processes. The model is implemented via COMSOL Multiphysics and validated by the simulation of THM processes which were monitored during operation of the FEBEX experiment and analysed during two dismantling phases of the experiment.