泥石流柔性防护系统耦合作用数值模拟

Coupled Numerical Simulation of Flexible Debris Flow Barrier

柔性防护系统近年来被广泛应用于交通沿线地质灾害的防治,但目前的相关研究主要集中在落石冲击作用下的力学响应,而遭受泥石流冲击作用的相关研究较少。泥石流与柔性防护系统的相互作用包括泥石流运动和柔性防护系统冲击大变形两个复杂的力学过程,目前尚无有效的耦合计算方法。为此,基于LS-DYNA程序,采用ALE方法,利用Drucker-Prager模型模拟泥石流的运动,并通过流固耦合算法,建立了考虑泥石流与柔性防护系统相互作用耦合计算方法。通过与既有野外足尺试验数据对比,包括泥石流流经沟槽不同位置时的速度、流深以及柔性防护系统钢丝绳内力、变形,验证了耦合计算方法的有效性。在此基础上,进一步研究了泥石流冲击作用下,冲击能量的平衡转换关系,结果表明:柔性防护系统消耗的能量占泥石流冲击总动能的比例不到25%,将近60%冲击能量转换为泥石流内能,这进一步说明了采用耦合方法进行泥石流柔性防护系统分析与设计的必要性。

In recent years,flexible barriers have been widely used in the prevention and control of geological disasters along railways,but the researches are mainly focused on the impact of rockfall,and few related studies focus on the impact of debris flow.The interaction between debris flow and flexible barrier includes two complex mechanical processes:debris movement and large deformation of the flexible barrier.At present,there is no effective coupled numerical simulation method.Therefore,in this paper,a coupled method to simulate the interaction between debris flow and the flexible barrier is established based on ALE method using LS-DYNA.In this method,Drucker-Prager model is adopted to describe the movement of debris flow.Compared with the existing full-scale test,including the flow velocity and flow depth of debris flow,as well as the internal force and deformation of flexible barrier,the validity of the coupling method is verified.Then,the transformation of the impact energy of debris flow is further studied.The results show that only 25%of the impact energy of the debris was dissipated by the flexible barrier,and there was about 60%of the impact energy transferred to the internal energy and dissipated by the debris flow itself.The results further explain the necessity to analyze and design flexible debris barriers by the coupling method.