Numerical simulation of root slope under rainfall based on PFC

In the traditional simulation of a slope with roots, the finite element method based on the continuum model is generally used to simulate the interaction between roots and soil by taking the roots and soil as a whole and giving the same parameters. Although the stress and deformation characteristics of slope soil and the stress changes around the rod element can be obtained basically equivalently at the macro level, it is difficult to reflect the tensile and bending behavior of root system in soil, which has obvious limitations. By coupling computational fluid dynamics (CFD) with the discrete element method (DEM), a numerical calculation model of the slope with roots under rainfall scouring is established to analyze the changes of parameters in the process of landslide under rainfall. The results show that during the failure process of the slope with roots simulated by the DEM-CFD fluid-structure coupling method, the force chain of soil particles and the meso parameters such as porosity will change during the rainfall process. For example, the porosity in the particle element grid at the top of the slope is much larger than that in the initial state. Through the analysis of the change of particle meso parameters, the mechanism of root slope consolidation under the action of precipitation is explained from the meso point of view. The research results provide a certain reference for the establishment of a calculation model of the slope with roots, and provide a new idea to better analyze the mechanism of root slope reinforcement from the micro point of view.