DISCRETE AND CONTINUUM APPROACHES TO SIMULATE THE THERMO-HYDRO-MECHANICAL COUPLINGS IN A LARGE, FRACTURED ROCK MASS

The study of coupled thermal, mechanical and hydraulic phenomena in fr actured rock mass like granite is of major importance for underground wastes repositories. There exist two possible approaches to model a hi ghly fractured rock mass: either represent each fracture individually or use an equivalent continuum, These two approaches have been compare d in the frame of a bench mark test (BMT1) on an hypothetic regularly fractured medium hosting nuclear wastes, The methodologies, as well as the algorithms used by the various research teams who participated in the exercise, are presented in detail. The thermal and mechanical res ults compare rather well, while hydraulic results show pronounced diff erences which can be partly attributed to the non-linear dependance of the fracture hydraulic conductivity in terms of the aperture.