拱坝沿建基面上滑溃决的可变形离散元仿真

三维可变形离散元是模拟不连续介质力学行为的有效数值分析方法,由于其采用显式有限差分方法以及自动进行离散缝面的接触检测,适合于求解弹塑性、大变形和动力问题。本文首先介绍了三维可变形离散元的基本原理及特点,然后对1981年梅花拱坝的溃坝过程进行仿真研究。通过分析得知,梅花拱坝由于周边缝施工设计不当,沿周边缝抗剪强度过小,导致蓄水后坝肩推力促使坝体沿周边缝发生整体上滑,拱坝失去支撑最终坝体断裂并溃决。

Simulation of upward-sliding failure of interface in arch dams by deformable distinct elements

3D deformable distinct element method (3D DEM) is an efficient numerical tool for simulation of mechanical behaviors of discontinuous media. It is suitable to use this method to analyze problems of elasto-plastic, large deformation and dynamic systems because of the use of the explicit finite-difference scheme and the automatic contact detection method for discretized joints. Herein, the principles and features of the 3D deformable distinct element method were described and the failure process of Meihua Arch Dam in 1981 was simulated. It is evident that abutment thrust due to the reservoir load leads to the upward sliding of the dam along the peripheral joints due to the weak shear resistance of peripheral joints, thus causing the rapid collapse of the dam.