Dynamic Damage and Crack Propagation of Granite under Thermal Shock: DEM Modeling Insights

Rocks in enhanced geothermal systems (EGS) are often subjected to both thermal shock and dynamic loading. In this study, we use the discrete element method (DEM) to develop a numerical model of granite and systematically investigate crack evolution and damage under the combined effects of sinusoidal dynamic loading and thermal shock applied after cooling. Results show that the highest crack formation occurs during cooling, primarily as tensile and tensile-shear cracks. Crack density increases with both thermal shock temperatures and the number of dynamic load cycles. At a high-temperature case studied (500°C), mechanical properties deteriorate significantly, accompanied by extensive crack development. DEM simulations visualizing crack propagation and damage evolution provide critical numerical insights for reservoir stimulation and wellbore stability assessment in EGS.