地震作用下危岩体倾倒破坏过程的数值模拟

Numerical simulation of toppling failure process of dangerous rock mass under earthquake

危岩体的倾倒崩塌破坏是一种常见的地质灾害,在露天采矿工程中,频繁的爆破作业会对边坡危岩体造成强烈的动力扰动作用,对于边坡危岩体在动力扰动作用下的破坏机理分析至关重要。本文以某露天煤矿危岩体为研究对象,采用FLAC-PFC耦合的数值模拟方法,从微观角度研究了地震作用下该类边坡破坏模式的破坏机理和破坏过程。连续-离散耦合的方法解决了有限差分法和颗粒离散元法模拟边坡受动力作用破坏过程的不足。研究结果表明,危岩体受到地震作用时,结构面上部开始产生张拉裂隙,逐渐向下贯通直至危岩体相对薄弱处,并以此为转动点产生倾倒破坏。地震作用下危岩体倾倒崩塌破坏过程主要分为四个阶段:相对稳定阶段、破裂贯通阶段、倾倒滑动阶段、碰撞破碎阶段。

Toppling failure of dangerous rock mass is a common geological disaster.In open-pit mining engineering,frequent blasting operation will cause strong dynamic disturbance to dangerous rock mass,so it is very important to analyze the failure mechanism of dangerous rock mass under the dynamic disturbance.Taking the dangerous rock mass of an open-pit mine as the research object,the failure mechanism and failure process of this type of rock mass under earthquake are studied from the microscopic point of view by using the FLAC-PFC coupling numerical simulation method.The continuous-discrete coupling method solves the shortcomings of finite difference method and particle discrete element method in simulating the failure process of slope under dynamic.The research results show that when the dangerous rock mass is subjected to earthquake,tensile cracks begin to occur on the structural plane,and gradually penetrate downward until the vulnerable rock mass is relatively weak,and toppling failure occurs with the weak point as the turning point. The toppling failure process of dangerous rock mass under earthquake can be divided into four stages: relatively stable stage, fracture penetration stage, toppling-sliding stage and collision-crushing stage.