Shear behavior of thermally damaged rock using the bonded-particle model based on moment tensor

It is critical to understand the temperature-dependent shear behavior of rock in exploiting deep natural resources-geothermal energy, coal, and oil. The shear behavior of thermally damaged rock needs to be further clarified from a micromechanical perspective. In this study, a series of direct shear tests are performed on thermally damaged sandstone using the bonded-particle model (BPM) with thermal formulation to investigate the temperature-dependent behavior. The macro mechanical properties and micro acoustic emission (AE) responses based on a moment tensor algorithm are derived from numerical models to provide insight into the temperature dependence of the mechanical behavior of sandstone. The simulated results indicate that high temperature can induce microcracks, a form of thermally induced damage. Thermally induced damage is a principal cause of the degradation of rock's mechanical properties. Generally, the maximum magnitudes of tensile, shear, and implosive events that can be tolerated without damage decrease gradually as the temperature increases. Also, AE b-value are closely associated with temperature. The findings of this study provide new insights into the shear responses and failure behaviors of rocks at different temperatures, and further aid deep natural resource exploitation when thermal and mechanical properties are coupled. The findings of this study provide new insights into the shear responses and failure behaviors of rocks at different temperatures. These insights could be valuable for optimizing deep natural resource exploitation, particularly when considering the coupling of thermal and mechanical properties.