Numerical simulation of coupled thermo-hydro-mechanical behavior for engineered barriers in high-level radioactive waste disposal

Following the need for understanding and quantifying the stability and security of the nuclear waste disposal repository, the coupled thermo-hydro-mechanical behavior of engineered barriers is studied. Bentonites are often envisaged as the main component of engineered barriers. These barriers are always subjected to thermal loading due to the heat emitted by the waste and to hydration from the water coming from the adjacent rock. Based on 2D axisymmetric analysis, finite element modelling of an in-situ large scale experiment is carried out by using ABAQUS. The simulated large scale experiment, called CLAB, is designed in the underground research facility in Sweden. The spatial distribution and variation law of temperature, saturation, pore pressure, suction, vertical stress and displacement in the engineered barrier are investigated. Special attention is given to the temperature effect on saturation, pore pressure, suction, vertical stress and displacement. The results of the finite element modelling of the CLAB experiment are compared with the in-situ measurements and some other computation data using different methods. The proposed modelling and simulating procedures are validated from the good agreement between predictions and in-situ measurements.