Sliding and accumulation characteristics of loose materials and its influencing factors based on discrete element method

Abstract

Loose materials has loose structure and is the main source of geological disasters such as collapses and landslides. Its hazard range is greatly affected by factors such as stone content and slope. Traditional studies on the sliding and accumulation characteristics of loose materials were mostly macro or qualitative analysis. There is little research on the micro internal motion mechanism. In the present study, discrete element method was used to quantitatively analyze the influence of stone content and slope variation on the characteristic values of loose particles such as stroke, accumulation width, maximum thickness, accumulation area, accumulation contour shape, accumulation volume, static accumulation angle and the cumulative mass. In the meanwhile, the movement and accumulation characteristics of the loose materials during the catastrophe process were explored from the aspect of energy and contact force of the particles, so as to reveal the interaction mechanism between the particles. The results showed that: When the stone content increased in the range of 0 to 70%, the stroke, accumulation width and accumulation area increased firstly and then decreased, and in the end the cumulative mass decreased. As the slope increased from 30° to 65°, the stroke, accumulation width, accumulation area and accumulation mass increased; the maximum thickness decreased approximately linearly, while the static accumulation angle had a decrease similar to quadratic function. In addition, there was a critical distance <i>L</i>_c for the volume share of coarse and fine particles in the accumulation area. When the distance from the toe line was <i>L</i> < <i>L</i>_c, the fine particles were larger than the volume of the coarse particles; when <i>L</i> > <i>L</i>_c, the fine particles were smaller than the volume occupied by coarse particles.