Abstract A new fluid–solid coupled numerical approach by combining the Dynamic Fluid Mesh method with DEM (discrete element method) is applied to simulate suffusion. The fluid mesh is generated according to the soil skeleton formed by coarse particles and updated at regular intervals. Seepage forces are calculated and applied on solid particles in the DEM model. The new approach accounts for permeability and porosity changes due to soil skeleton deformation and suffusion. A model of soil sample under triaxial stress condition is developed to simulate the suffusion process. The results show that the erosion process can be divided into three stages: initial stage when numerous fine particles are washed away and the flow rate increases with more eroded particles, deceleration stage when the erosion rate decreases and the flow rate tends to reach a steady state, and stabilization stage when the erosion rate levels off to zero gradually. Parametric studies show that the increase of hydraulic gradient and coarse particle size ratio both increase the eroded particle mass. However, high confining stress will decrease the eroded particle mass. Hydraulic gradient affects the whole process of suffusion whereas confining stress and particle size ratio mainly affect the second and third stages.

中文翻译：

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通过将离散元方法与动态流体网格耦合来模拟流体 - 粒子相互作用：对间隙分级土壤中的扩散的影响

摘要 将动态流体网格法与DEM（离散元法）相结合，采用一种新的流固耦合数值方法来模拟扩散。流体网格是根据粗颗粒形成的土骨架生成的，并定期更新。在 DEM 模型中计算渗流力并将其应用于固体颗粒。新方法考虑了由于土壤骨架变形和扩散引起的渗透率和孔隙率变化。建立了三轴应力条件下的土样模型来模拟扩散过程。结果表明，冲蚀过程可分为三个阶段：初始阶段，大量细颗粒被冲走，流速随着被冲蚀颗粒的增加而增加；减速阶段，冲蚀速率减小，流量趋于稳定，冲蚀速率逐渐趋于平稳，稳定阶段。参数研究表明，水力梯度和粗粒度比的增加都增加了侵蚀颗粒的质量。然而，高围压将减少被侵蚀的颗粒质量。水力梯度影响整个扩散过程，而围压和粒度比主要影响第二和第三阶段。