ABSTRACT
In the underground surrounding rock engineering (underground coal gasifier, nuclear waste disposal repository), the surrounding rock will sometimes be under high temperatures. To explore the effect of high temperature on mechanical behavior and fracture characteristics of rock, the mechanical properties, fracture information, and fracture mode of rock were discussed by processing the AE information during rock fracture. The results show that there is an obvious temperature effect on the mechanical properties of granite. The high temperature of 200°C and 400°C can significantly enhance the brittleness of granite, and the AE counts are concentrated near the peak stress. 600°C can significantly reduce the mechanical parameters of rock, resulting in many AE counts during the compaction and elastic stages. The leading role of shear cracks in rock failure mode can be enhanced by increasing the confining pressure. With the increase in temperature, the rock exhibits a transition from “tension-split failure” to “tension-shear conjugate failure.” Based on the two rock strength criteria, it is found that m b shows opposite changes to elastic modulus and rock brittleness; cohesiveness is positively correlated with elastic modulus and rock brittleness. The research results have certain reference values for the study of rock mechanics after high temperatures.
