The discrete element method (DEM) is widely used in the realistic simulation of the shapes of particles. Researchers have considered the simplification of particle shapes owing to the high computational cost of such simulation. In this regard, the modeling of calibrated particles is a major challenge owing to the simultaneous effects of particle properties. The angle-of-repose test is a standard test method used to calibrate the bulk behavior of simulated particles. In the present study, the hollow-cylinder (slump) test was modeled for the verification of discrete element simulations. In this regard, a sensitivity analysis was conducted for all effective parameters, namely the static friction, rolling friction, restitution coefficient, sphericity, roundness, particle size distribution, and number of ballast particles. The results indicate that the rolling friction, roundness, number of particles, and size of particles are the most important parameters in the determination of the angle of repose (AOR). For particles in the range of ballast (20–60 mm), the effect of the number of particles on the angle of repose is reduced when the number is greater than 426. Additionally, it is concluded that angular particles can be replaced with sub-angular particles (R ≈ 0.2–0.45) with a higher rolling friction coefficient (μ_r > 0.14).

离散元法（DEM）广泛用于颗粒形状的真实模拟。由于这种模拟的计算成本很高，研究人员已经考虑过简化粒子形状。在这方面，由于粒子属性的同时影响，校准粒子的建模是一个主要挑战。休止角测试是用于校准模拟粒子的整体行为的标准测试方法。在本研究中，空心圆柱体（坍落度）试验被建模以验证离散元模拟。对此，对所有有效参数进行了敏感性分析，即静摩擦力、滚动摩擦力、恢复系数、球形度、圆度、粒度分布和道碴颗粒数。结果表明，滚动摩擦、圆度、颗粒数量和颗粒尺寸是确定休止角（AOR）的最重要参数。对于压载范围（20-60 mm）的颗粒，当颗粒数量大于426时，颗粒数量对休止角的影响减小。具有较高滚动摩擦系数 (μ_r > 0.14）。