基于DEM的碎屑流运动特性数值模拟

采用颗粒离散元法建立了碎屑流三维数值模型,分别从整体和局部对碎屑流运动特性进行深入分析。结果表明:碎屑流的运动过程可分为启动加速、高速滑动和减速堆积3个阶段;边坡底面平整时,堆积体中大颗粒堆积在表面,而细小颗粒位于中下部位;碎屑流运动速度和能量损失受颗粒间的接触碰撞影响大;碎屑流不同部位运动速度最大值相同,达到速度峰值的时间与颗粒的初始水平位置有关,与深度无关;堆积体分区明显,堆积体中的颗粒按初始水平位置依次排布;坡脚位置堆积深度最大,往两侧逐渐减小;碎屑流在运动初期和末期横向运动明显,扩大了灾害影响范围。

Numerical simulation of movement characteristics of debris flow based on DEM

A three-dimensional numerical model for debris flow was established with the particle discrete element method(DEM), and the movement characteristics of debris flow were analyzed from the full and local aspects. The results show that the movement process of debris flow can be divided into three stages, including starting acceleration, high-speed sliding, and reduced-speed deposit. When the bottom of the slope is flat, large particles are found on the surface of the deposition body, but small particles are in the middle and low areas. The velocity and energy loss of debris flow is significantly influenced by the contacts and collisions between particles. The maximum speeds of different parts of the debris flow are almost the same, and the time required to reach the speed peak is related to the initially horizontal position of particles, but not related to the deposit depth. Area division is distinct in the deposition body, and the particles of the deposition body are arranged according to their initially horizontal positions. The maximum deposit height is at the slope toe, and the deposit height gradually decreases towards both sides. Significant lateral movement occurs in the debris flow in the early and late stages, which can expand the scope of a disaster.