A Study on the Motion and Accumulation Process of Non-Cohesive Particles

In order to further understand the mechanism of landslide-debris flow and predict the entire movement process and accumulation range of landslide hazards, the movement process of non-cohesive particles and the distribution of accumulation at the bottom of the slope were studied. Firstly, physical laboratory-scale tests on the sliding accumulation process of non-cohesive granular accumulations under self-weight were carried out, and the effects of different volumes and gradations on the sliding accumulation were analyzed. Then, the discrete element software PFC3D was used to perform three-dimensional numerical back analysis of the tests to refine the key parameters required for the numerical simulation, and to understand better the movement and accumulation state of the granular body. The results showed that the spherical particles exhibit obvious lateral expansion during the acceleration stage, and the front-end particles had a clear "shuttle" distribution, which became even more obvious with the increase in the content of large particles. The reverse-order phenomenon of spherical particles after sliding was that the proportion of small particles in the proximal end was far higher than their original proportion in the accumulation body. With the increase in the volume of the accumulation body, the phenomenon became more obvious, and stopping of large particles above the small particles was observed. The research results can provide reference for further studies of the movement process and the distribution patterns of the slip instability failures of non-cohesive accumulation bodies.