Abstract:Under the high stress mining environment in the deep part, the internal joints and fissures of the rock mass develop, and the degree of fragmentation intensifies, resulting in a decrease in the bearing capacity of the surrounding rock of the roadway and prominent deformation and damage problems. This article uses a discrete fracture network (DFN) to construct a tunnel model with a certain fragmentation structure, simulating the excavation process of tunnels with burial depths of 500m, 1000m, 1500m, 2000m, and2500m respectively. Combined with the theory of stress mechanics of surrounding rock in circular tunnels, the bearing structure characteristics of surrounding rock in tunnels under high stress environments are studied. Based on the stress distribution law of surrounding rock in tunnels with different burial depths, the bearing structure of surrounding rock was divided into zones, and the relationship between tunnel burial depth and plastic zone expansion was obtained, revealing the fracture characteristics of fractured rock mass under high stress. The research results can provide reference for the design of surrounding rock support in tunnels under similar mining conditions.
