Influence of particle angularity on the suffusion in gap-graded granular soils remains unclear up to now. In this study, systematical numerical simulations that consider the particle shape as quasi-spherical polyhedra in different angularity are performed with the coupled discrete element method (DEM) and the computational fluid dynamics (CFD) approach. The suffusion of six gap-graded soil samples with 25% fines content is examined by imposing an upward seepage flow. Conventional triaxial tests are also conducted on the pre-eroded and post-eroded specimens to study the coupling influence of angularity and suffusion on the mechanical characteristics of granular soils. Fines loss, vertical displacement, soil strength, volume flow rate, microstructural analyses of force networks, the cumulative percentage of contact force, and the anisotropy of contact are investigated. Results turn out that the angularity intensifies the internal erosion resistance as the fines loss decreases significantly with the increasing angularity. The soil peak strength and friction angle are approximately linearly correlated with angularity. Erosion-induced particle redistribution reduces the degree of anisotropy of contact normal and contact normal force. This study may improve our understanding of the effect of particle angularity on suffusion with both microscopic and macroscopic evidence.

颗粒棱角对间隙级配颗粒土中充盈的影响至今仍不清楚。在这项研究中，使用耦合离散元方法 (DEM) 和计算流体动力学 (CFD) 方法执行将粒子形状视为不同角度的准球形多面体的系统数值模拟。通过施加向上的渗流来检查六个具有 25% 细粒含量的间隙级配土壤样品的泛滥情况。还对侵蚀前和侵蚀后的试样进行了常规三轴试验，以研究棱角和扩散对粒状土力学特性的耦合影响。细粒损失、垂直位移、土壤强度、体积流量、力网络的微观结构分析、接触力的累积百分比、并研究了接触的各向异性。结果表明，随着棱角的增加，细粒损失显着减少，棱角增强了内部抗冲蚀能力。土壤峰值强度和摩擦角与角度近似线性相关。侵蚀引起的粒子重新分布降低了接触法向和接触法向力的各向异性程度。这项研究可以通过微观和宏观证据提高我们对粒子角度对扩散影响的理解。侵蚀引起的粒子重新分布降低了接触法向和接触法向力的各向异性程度。这项研究可以通过微观和宏观证据提高我们对粒子角度对扩散影响的理解。侵蚀引起的粒子重新分布降低了接触法向和接触法向力的各向异性程度。这项研究可以通过微观和宏观证据提高我们对粒子角度对扩散影响的理解。