Experimental and numerical investigation of coupled thermo-mechanical processes in porous media, with applications to deep geological repositories
University of New Brunswick
This research investigates the coupled thermo-mechanical effects in porous media. This has become a topic of interest in geotechnical and geological engineering due to emerging projects in this field, such as climate change in cold regions, geothermal energy, and the storage of spent nuclear fuel in deep geological repositories (DGRs). This research consisted of both experimental and numerical works. A focus of the experimental works included uniaxial compression strength tests of hypothetical constituents of a DGR, at the range of temperatures expected near the storage rooms of a DGR. The numerical work of this research was done using near and far field models of a hypothetical DGR. These models were utilized to predict the temperature and stress development around the storage rooms of a DGR, the effects of model geometry on temperature development, and thermo-mechanical analysis with temperature dependent properties obtained from the experimental portion of this research. The results of the experimental works found a small decrease in strength of rock when heated to 100 °C. Through numerical analysis it was found that: temperature development around the storage rooms of a DGR is highly influenced by room spacing; heat output of the spent fuel produced lower FOS as time and temperature progressed, and the rock remained stable over the 150-year analysis period. Lastly, inclusion of temperature dependent mechanical properties produced near negligible changes to the overall stability of the rock around the storage rooms of the DGR.