Soil erosion is a critical process that is being studied in soil science, hydraulic engineering, and geotechnical engineering. Among many societal and environmental impacts, soil erosion is a major cause for the failures of bridges. The erodibility of soil is determined by its physical and geochemical properties and is also affected by surrounding biological activities. In most of the current models for soil erosion, erodibility of non-cohesive soil is characterized by its median grain size (D₅₀), density, and porosity. The contribution to erodibility of the irregular shape of soil grains, which plays an important role in the mechanical and hydraulic properties of coarse-grained soils, is generally ignored. In this paper, a coupled computational fluid dynamics and discrete element method model is developed to analyze the influence of the shape of sand grain on soil erodibility. A numerical model for the drag force on spherical and non-spherical particles is verified by using the results from physical free settling experiments. Erosion of sand grains of different shapes is simulated in a virtual erosion function apparatus, a laboratory device used to measure soil erodibility. The simulation results indicate that the grain shape has major effects on erodibility. Spherical particles do not show a critical velocity because of their low rolling resistance, but a critical velocity does exist for angular particles owing to grain interlocking. The erosion rate is proportional to the flow velocity for both spherical and non-spherical particles. The simulation result for angular particle erosion is fairly consistent with the experimental observations, implying that grain shape is an important factor affecting the erodibility of non-cohesive soils.

土壤侵蚀是土壤科学，水利工程和岩土工程中正在研究的关键过程。在许多社会和环境影响中，水土流失是桥梁破坏的主要原因。土壤的易蚀性取决于其物理和地球化学性质，还受周围生物活动的影响。在大多数当前的土壤侵蚀模型中，非粘性土壤的侵蚀性特征在于其中值粒径（D ₅₀），密度和孔隙率。通常不理会对不规则形状的土壤颗粒的可蚀性的影响，这在粗粒土壤的机械和水力性质中起着重要作用。本文建立了一个耦合的计算流体动力学和离散元方法模型，以分析砂粒形状对土壤易蚀性的影响。通过使用物理自由沉降实验的结果，验证了对球形和非球形颗粒的拖曳力的数值模型。在虚拟的腐蚀功能设备（用于测量土壤可蚀性的实验室设备）中模拟了不同形状的沙粒的腐蚀。模拟结果表明，晶粒形状对可蚀性有很大影响。球形粒子由于其低滚动阻力而没有显示临界速度，但是由于晶粒互锁，角形粒子的确存在临界速度。对于球形和非球形颗粒，腐蚀速率均与流速成正比。角颗粒侵蚀的模拟结果与实验结果相当吻合，这表明晶粒形状是影响非粘性土壤易蚀性的重要因素。