Numerical Simulation of Evolution Mechanism of Rockburst Risk in Deep Rock Tunnels Under Anchor Rod Anchoring

The evolution mechanism of the bearing layer in the surrounding rock of tunnels with rockburst risk is extremely complex under bolt anchorage in deep strata. In this paper, the stress response, energy evolution, and crack development under different in situ stress levels and rock bolt quantities are systematically investigated. The results found that significant stress concentration and energy accumulation zones tend to form in the surrounding rock under high in situ stress conditions. The rapid unloading of radial stress and the sudden increase in kinetic energy are well-correlated in terms of time, representing important characteristics of dynamic rock failure. A significant decrease occurs in the maximum radial stress, kinetic energy, and strain energy of the surrounding rock as the number of rock bolts increases, while the number and connectivity of cracks notably weaken. This causes the failure process of the surrounding rock to transition from unstable to controlled development. It is indicated that rock bolt support can reduce the potential risk of rockbursts by regulating stress redistribution and energy release paths under high in situ stress. The findings provide a reference for evaluating surrounding rock stability and optimizing support parameters in deep-buried tunnels.