On the Microcrack Propagation and Mechanical Behavior of Granite Induced by Thermal Cycling Treatments

Deep geothermal energy is a renewable and environmentally friendly resource, the hot dry rock in reservoir subjected to thermal cycling treatment. Thermal treatment can cause stresses matrix result cracking, which significantly influence physical mechanical properties of rock. To investigate on microcrack propagation behavior granite rock, series tests were performed nontreated treated samples. The testing results show that mass, density, P-wave velocity decrease with heating temperature time increase, while volume samples increases significantly. UCS elastic modulus declined from 178.65 MPa 20.09 GPa 24.58 3.81 after at 500 °C for 30 times, respectively. degradation trends be characterized by times. High frequent induce within granite, causes failure leads transformation brittleness ductility.