Discrete element study on mechanical response and pressure relief effect of rock containing variable hole

Abstract

The traditional large-diameter hole pressure relief technology has the disadvantages of insufficient pressure relief in deep surrounding rock and damage to shallow surrounding rock. Therefore, an improved reaming hole pressure relief technology is proposed. A series of compression tests are conducted on numerical models with various hole parameters using the three-dimension particle flow code (PFC3D) to reveal the pressure relief mechanism of reaming hole technology. Firstly, numerical models for the pre-holed specimen are constructed, and the micro-parameters are calibrated based on the experimental results. Then, the evolution of crack initiation, propagation, and coalescence for pre-holed specimens are investigated by confined compression simulations in PFC3D. The relationships among the cracking process, stress-strain curve, and number of micro-crack are analyzed in detail. Finally, the spatial-temporal evolution of the stress field around the hole is discussed from the stress and force chain perspective. The research results could serve as a foundation for evaluating the pressure relief effect through stress and fracture monitoring methods on the surrounding rock mass.