Study of the Particle Shape Influence on Soil Erodibility Using Coupled CFD-DEM Modeling

摘要

Researches show erodibility of sand is mainly determined by the grain size, or the mass median diameter. The influence of particle shape on sand erodibility has been neglected for simplification. Here using a coupled CFD-DEM method, the influence of sand particle shape on soil erodibility has been analyzed. The model was built prototyping from the Erosion Function Apparatus (EFA) developed by Briaud, where soil sample inside a Shelby tube is extruded into a rectangular flow channel with an extrusion height of 1 mm, and subjected to the erosion of flowing water. Critical shear stress and erosion rate of the soil sample can be obtained through the EFA test. In the simulating cases, spherical particles and non-spherical particles with aspect ratios of 1.10, 1.20 and 1.30 have been tested and compared. The results show grain angularity plays an important role in the formation of erosion resistance. For spherical particles, due to the lack of rolling resistance, no critical velocity has been observed. For non-spherical particles, with the increase of aspect ratio, the critical velocity increases indicating a higher erosion resistance. Erosion rate increases linearly with flow velocity, which is consistent with experimental studies.