Numerical Simulation of Fine Particle Migration in Loose Soil Under Groundwater Seepage Based on Computational Fluid Dynamics-Discrete Element Method

The seepage of groundwater in loose soil causes the migration of fine particles within the soil, which can significantly contribute to slope instability and trigger a series of geological issues, such as soil erosion, landslides, and debris flow. This study employed a coupled computational fluid dynamics and discrete element method (CFD-DEM) to investigate the migration process of soil particles under groundwater seepage. It elucidated the effects of key factors, including particle size ratio, particle quantity, and weight, on the migration behavior of fine particles within porous media. The results indicated that when the particle size ratio was less than or equal to 5, over 90% of fine particles accumulated on the surface of the medium. Additionally, an increase in the weight or quantity of fine particles intensified their accumulation. However, when the particle size ratio exceeded five, it became the dominant factor affecting displacement. Under the same weight conditions, the larger the particle size ratio, the longer the particle migration distance. Compared to a particle size ratio of 3, the accumulation percentages of fine particles with a particle size ratio of 20 increased by 26.88% and 31.46% in the middle and tail sections, respectively.