Calculation model for kinetic energy and rock burst risk evaluation method during roadway excavation

The accumulation and release of deformation energy within the rock mass of a roadway are primary contributors to the occurrence of rock bursts. This study introduces a calculation model for the kinetic energy generated during roadway excavation, which is based on the fracture and energy states of the rock mass. The relationships among the mining depth, width of the plastic zone, rebound range of the roof and floor, stress concentration factor, and the induced kinetic energy are systematically explored. Furthermore, a rock burst risk evaluation method is proposed. The findings indicate that the energy evolution of the rock mass can be categorized into four stages: energy accumulation due to in-situ stress, energy accumulation resulting from coal compression, energy dissipation through coal plastic deformation, and energy consumption due to coal failure. The energy release from the rock mass is influenced by several factors, including mining depth, stress concentration factor, the width of the plastic zone, and the rebound range of the roof and floor. Within the plastic zone of coal, the energy released per unit volume of coal and the induced kinetic energy exhibit a nonlinear increase with mining depth and stress concentration factor, while they decrease linearly as the width of the plastic zone increases. Similarly, the driving energy per unit volume of the roof and floor shows a nonlinear increase with mining depth and stress concentration factor, a linear increase with the rebound range of the roof and floor, and a linear decrease with the width of the plastic zone. A rock burst risk evaluation method is developed based on the kinetic energy model. Field observations demonstrate that this method aligns with the drilling cuttings rock burst risk assessment method, thereby confirming its validity.