基于物质点法的远程滑坡碎屑流运动过程模拟及特征分析

Process Simulation and Characteristics Analysis of Long Run-out Debris Flow Movement Based on Material Point Method

目的 研究远程滑坡碎屑流运动过程以及运动过程中速度、滑动距离、动能变化,为滑坡碎屑流灾害的预防和治理提供参考。方法 基于物质点法,以塔合曼和乱石包两个远程滑坡碎屑流工程实例为背景,对两个滑坡碎屑流的运动过程进行数值模拟;并对塔合曼滑坡碎屑流运动过程中水平、垂直方向运动速度分布,内摩擦角对运动过程的影响,以及乱石包滑坡碎屑流铲刮效应对堆积形态、动能变化的影响进行分析。结果 两个滑坡碎屑流最终堆积形态模拟结果与实测结果吻合良好,验证了数值模拟结果的有效性;塔合曼滑坡碎屑流随着内摩擦角从18°增加到33°,动能峰值降低71.4%,最终势能增加54.4%,滑坡碎屑流的能量耗散减小47.8%;在乱石包滑坡碎屑流实例的模拟中,速度云图呈现了滑体速度场的层状分布特征。结论 内摩擦角对滑坡碎屑流的动力过程影响十分显著;乱石包滑坡碎屑流的滑体在高速滑移阶段存在强烈的内部剪切作用,并且铲刮效应对滑坡碎屑流的运动起到了一定的阻碍作用。

The purpose is to study the process of long run-out debris flow movement,as well as the changes in velocity,sliding distance,and kinetic energy during the movement,in order to provide reference for the prevention and treatment of debris flow disasters.Based on the material point method,numerical simulation analysis was conducted on the movement process of two long run-out debris flow engineering examples,Taheman and Luanshibao,using them as background.The horizontal and vertical velocity distribution during the Taheman debris flow movement process,the influence of internal friction angle on the movement process,and the impact of the entrainment effect of Luanshibao debris flow on the accumulation form and kinetic energy changes were analyzed and discussed.The simulation results of the final accumulation form of two debris flows are in good agreement with the measured results,verifying the correctness and effectiveness of the numerical simulation results.As the internal friction increases from 18°to 33°,the peak kinetic energy of the Taheman debris flow decreases by 71.4%,and the final potential energy increases by 54.4%.The energy dissipation of the debris flow decreases by 47.8%.In the simulation of Luanshibao debris flow,the velocity distribution shows the laminar distribution of the velocity field.The internal friction angle has a significant impact on the dynamic process of the debris flow.The sliding mass of Luanshibao debris flow has a strong internal shear effect in the high-speed sliding stage,and the entrainment effect has played a certain role in blocking the movement of the debris flow.