Damage Characteristics of Prefabricated Fractured Granite after High Temperature

Temperature is one of the important factors affecting the physical and mechanical properties of rock. The study of the influence of high temperature on the evolution of rock mechanical properties and damage mechanism is of great significance in the construction of deep rock mass engineering. Based on the PFC particle flow numerical simulation method, the uniaxial compression experiments of pre-existing flaws granite treated at different temperatures (20 ℃,200 ℃,400 ℃,600 ℃,800 ℃) were simulated. The results show that the peak strength and elastic modulus of granite decrease significantly with the increase of heat treatment temperature, while the peak strain increases. The degree of thermal damage caused by different heat treatment temperatures varies, leading to differences in macroscopic failure modes of prefabricated fractured granite. When the heat treatment temperature does not exceed 600 ℃, the granite undergoes failure along both ends of the prefabricated crack; When the heat treatment temperature reaches 800 ℃, thermal damage becomes the dominant factor in the mechanical failure mode of granite, and the degree of fragmentation significantly increases. The research results contribute to understanding the mechanism of rock damage evolution under high temperature, and can provide reference for deep underground engineering.