不同位移模式下挡土墙的模型试验及数值模拟

 使用角钢和高强度的有机玻璃，结合按照原型比例设计的尺寸，自制挡土墙模型箱。测试挡土墙在不同运动状态下，墙后土体的水土压力分布，获得剪切带的细观参数。在模型试验基础上，通过二次开发PFC2D颗粒流程序对砂土挡土墙进行离散元仿真模拟。研究不同位移模式：平移(T)、绕墙底转动(RB)、绕墙顶转动(RT)，以及2种组合位移模式：绕墙底以下某点转动(RBT)、绕墙顶以上某点转动(RTT)下挡土墙被动破坏机制。分析挡土墙运动过程中侧压力的变化、土体位移场和变形以及挡土墙到达一定位移时颗粒集合体内部的剪应变率分布。通过对比分析模型试验结果与数值模拟结果，结果表明，墙后土体水土压力的模拟结果与试验结果吻合很好，反映水土压力的分布规律。

MODEL TEST AND NUMERICAL SIMULATION OF RETAINING WALL UNDER DIFFERENT DISPLACEMENT MODES

Combined with the size designed by prototype proportion，the model box is self-developed by using angle iron and organic glass with high strength. The water and soil pressure distributions and the micro-parameters of the shear zone behind retaining wall are tested under different displacement modes. Based on the model test，using secondary development particle flow program PFC2D ，the sand retaining wall is simulated by discrete element method. The passive failure mechanisms of the retaining wall are studied under different displacement modes. The different wall movement modes including three kinds of basic modes，i.e. translation(T)，rotation about base(RB)，rotation about top(RT) and two combinational modes，i.e. rotation about the point below base(RBT)，rotation about the point above top(RTT). Changes of lateral pressure，soil displacement field and deformation，and the particle aggregate internal shear strain rate distribution when the retaining wall reach a certain displacement are analyzed. Numerical simulation results indicate that the retaining wall of active and passive earth pressure simulation results are basically consistent with experimental test results；and the influence law of soil pressure distribution can be better reflected as the retaining wall under different displacement modes.