Simulating the Failure Mechanism of High Slope Angles Under Rainfall-Mining Coupling Using MatDEM

The safety production of gold, silver, copper, and other important metals is seriously threatened in the process of mining from open-pit to underground due to various factors such as infiltration caused by rainfall and unloading during mining. Furthermore, the current situation of open-pit mining in an increasing number of mines presents a high and steep terrain, which poses significant security risks. Accordingly, it is of great practical significance to investigate the failure mechanism of high slope angles to ensure the long-term safe mining of mines, considering factors such as rainfall infiltration and excavation unloading. In this study, the slope failure of high slope angles (45°, 55°, and 65°) under rainfall-mining coupling was analyzed using the discrete element MatDEM numerical simulation software. Herein the stress distribution, failure characteristics, and energy conversion of the model were simulated under different slope angles to analyze the failure mechanism at each stage. The numerical simulation results indicate that the steeper the slope angle, the more severe the damage. Moreover, the reduction of elastic potential energy during the mine room mining stage is similar to that of mechanical energy. During the pillar mining stage, stress is concentrated in each goaf, resulting in a greater reduction of mechanical energy compared to elastic potential energy. Ultimately, after the completion of the continuous pillar mining stage, stress becomes concentrated in the failure area, and the effect of slope angle on mechanical energy reduction becomes evident after complete collapse of the model.