Abstract:Rainfall intensity and terrain slope are two important dynamic factors that produce runoff sorting characteristics in the surface moraine area. This paper takes the surface moraine particles in the Shangri-Lapulang copper mine as the research object. The indoor artificial simulated rainfall test method was used. The variation law of moraine runoff sorting characteristics under different rainfall intensities (200, 400, 600 mL/(min·m2)) and slopes (10°, 21°, 32°) was studied. Research indicates: The moraine particles have a significant sorting effect in the process of runoff scouring with different rain intensities and slopes. Under different rain intensities and gradient conditions, the particle size of moraine particles by scouring and sorting is selective, and the particles with smaller particle sizes are preferentially sorted. And the smaller the rain intensity and slope, the finer the particle size of runoff sorting. The mass proportion of particles in the runoff sorting showed a change law of first increasing and then decreasing with the increase of the slope, indicating that there was a critical gradient in the change of the particle size in the runoff sorting. The research results can formulate effective measures for the prevention and control of runoff sorting of moraine particles, to prevent the fine-grained moraine particles after runoff sorting from entering the scope of mining activities. It is of great significance to the prevention and control of underground debris flow disaster accidents in mines.