Study on mechanical damage mechanism of initial crack and water content to free face rock

Abstract

The surrounding rock of the underground cavern at Yebatan Hydropower Station is faced with the combined action of fault cutting and rich groundwater. After the excavation of underground cavern, the relaxation deformation and the stability analysis of free face rock have always been the focus of the engineering. Based on this, this paper constructs rock specimens with different types of initial cracks and different water content, and places them in a special mold which can simulate the free face for compression testing. In this paper, the strength, deformation and failure characteristics of the rock specimens with different initial rack types and water content combinations are studied, and the sensitivity of crack types and water content to the mechanical properties of free face rock is also analyzed. The specimens with typical failure characteristics are selected for microscopic scanning to obtain the microscopic damage pattern, the relationship between the microscopic damage and the macroscopic failure of the free face rock under the action of complex factors is established. This study can provide reference for the stability analysis of surrounding rock with similar background.