Physical modeling and numerical simulation of selected THM-coupled processes in claystone rock mass

For final radioactive waste disposal besides granite formations (Sweden, Switzerland) clay formations are investigated as host rocks (France, Switzerland, Belgium). In Germany besides the salt deposits also clay deposits are available in relevant depths and extensions so that the use as host rocks for high-level waste repositories seems to be possible. The knowledge on mechanical and hydraulic properties is still rather low. The physical modeling of the rocks concerns predominantly the reproduction of deformation and strength and hydraulic properties by appropriate mechanical and hydraulic models based on measured deformations dependent on mechanical loads, temperature, moisture content and humidity. Due to the observed coupling of the time dependent deformations and hydraulic flow processes the basic questions concerns the deformation mechanism. The hydro-mechanical coupled process code FLAC3D has significant deficiencies with respect to mine aeration effects on the pore water pressure, therefore supplementary simulations were performed using the code CODEBRIGHT. Due to the complex thermal, hydraulic, mechanical and chemical (THMC) effects on the material behavior the simulation of the long-term safety of a repository is not possible without extensive knowledge on the fundamental processes and mechanisms. Extensive experimental research is still necessary.