The paper deals with three-dimensional simulations of a monotonic quasi-static interface behaviour between cohesionless sand and a rigid wall of different roughness during wall friction tests in a parallelly guided direct shear test under constant normal stress. Numerical modelling was carried out by the discrete element method (DEM) using spheres with contact moments to approximately capture a non-uniform particle shape. The varying wall surface topography was simulated by a regular mesh of triangular grooves (asperities) along the wall with a different height, distance and inclination. The calculations were carried out with different initial void ratios of sand and vertical normal stress. The focus was to quantify the effect of wall roughness on the evolution of mobilized wall friction and shear localization, also to specify the ratios between slip and rotation and between shear stress/force and couple stress/moment in the sand at the wall. DEM simulations were generally in good agreement with reported experimental results for similar interface roughness. The findings presented in this paper offer a new perspective on the understanding of the wall friction phenomenon in granular bodies.

本文在平行法向直接剪切试验中，在恒定法向应力下，对无粘性砂与具有不同粗糙度的刚性壁之间的单调准静态界面行为进行了三维模拟。通过离散元素方法（DEM）使用具有接触力矩的球体近似捕获不均匀的颗粒形状来进行数值建模。通过沿着壁以不同的高度，距离和倾斜度进行规则的三角形沟槽（粗糙）网格来模拟变化的壁表面形貌。计算是在不同的沙初始空隙率和垂直法向应力下进行的。重点是量化壁面粗糙度对动员壁面摩擦和剪切局部化演变的影响，还应指定滑移和旋转之间的比例，以及墙体沙子中的剪应力/力和耦合应力/力矩之间的比率。对于相似的界面粗糙度，DEM模拟通常与报告的实验结果完全吻合。本文提出的发现为理解粒状体中的壁摩擦现象提供了新的视角。