Rainfall–Mining Coupling Effects on Slope Failure Mechanism and Evolution Process: A Case Study of Open-Pit to Underground Mining

Abstract

This research examines how rainfall and mining affect the slope damage resulting from the transition from open-pit mining to underground mining. Using an unmanned aerial vehicle (UAV), the Huangniu slope of the Dexing Copper Mine was fully characterized, and experiments were conducted on rock samples from appropriate sites. First, the mechanical properties of the samples were measured. Then, the parameters of the similarity simulation experiments were derived based on the similarity theory. Subsequently, the rainfall, rock slope, data acquisition, and monitoring systems were designed. Finally, the rock mass failure with different slope angles was analyzed, and the deformation and damage patterns under the coupling effect were obtained. The results show that rainfall increases pore water pressure and moisture content. Rainfall and slope-slip water have more of an impact on the open-pit platform. The pore water pressure values on the upper rock mass rise faster than inside it. In the open-pit mining stage, the rock mass shifts slightly to the upper left. In the room mining stage, vertical fractures and goaf sinking occur. The fractures above the mine form a semi-ellipse. In the pillar mining stage, overlying rock displacement is evident and fractures persist. In the continuous pillar mining stage, the overlying rock collapses. The 65° slope model was the most damaged, while the 55° slope model was the least damaged. The results also suggest that the UAV guides sample selection.