Abstract Sandy soils may become unstable under loading which causes large deformations and consequently, impose damages to existing structures. In this research, Discrete Element Method (DEM) is used to simulate 2D drained and undrained behavior of polygonal granular materials to investigate instability occurrence. The so-called cylinder method is applied to simulate the undrained behavior that a pipe is assumed between neighboring pores to allow fluid flow. The applicability of this method was evaluated with constant-volume approach. The advantage of the cylinder method is to assess the distribution of fluid pressure. Comparison of the results indicate good match. Based on both drained and undrained simulations, a unique critical state line was obtained; however, the position of instability line was influenced by the initial void ratio. At the onset of potential instability, the central pore pressure increases highly; however, it reduces afterwards and the fluid pressure is almost distributed uniformly throughout the sample.

中文翻译：

---

使用离散元法 (DEM) 对多边形颗粒进行双轴加载时饱和颗粒材料的不稳定性

摘要 沙土在荷载作用下可能会变得不稳定，导致大变形，从而对现有结构造成破坏。在本研究中，离散元方法 (DEM) 用于模拟多边形颗粒材料的二维排水和不排水行为，以研究不稳定的发生。所谓的圆柱方法用于模拟不排水行为，即在相邻孔隙之间假设管道以允许流体流动。该方法的适用性通过定容法进行评估。气缸法的优点是可以评估流体压力的分布。结果的比较表明匹配良好。基于排水和不排水模拟，获得了独特的临界状态线；然而，不稳定线的位置受初始空隙率的影响。在潜在不稳定性开始时，中心孔隙压力高度增加；然而，之后它会降低并且流体压力几乎均匀地分布在整个样品中。