地震作用下陡岩崩塌颗粒离散元数值模拟研究

 基于江坪河水电站陡岩边坡，进行块体倾覆分析确定地震影响下潜在的破坏位置，推导地震波在颗粒介质内中传播时的边界条件设置公式，用二维颗粒离散元模拟分析地震作用下陡岩的崩塌灾害。结果表明：基于颗粒离散元的崩塌灾害分析方法可通过颗粒运动轨迹来判断边坡是否稳定，研究边坡破坏扩展过程，并可通过修改边界颗粒的属性来模拟入射地震波及透射边界，可最大限度模拟荷载–岩性–灾害发展的耦合作用；地震作用下顺坡向陡倾角卸荷裂隙发育是影响陡岩边坡稳定的控制性结构面，表层发生局部崩塌、块体失稳的可能性较大，其破坏机制为高烈度地震作用下从表层局部块体崩落开始，继而沿着节理裂隙快速扩展直至上部岩体产生崩塌，破坏规模则主要取决于顺层向裂隙的发育深度。该方法可为崩塌失稳边坡的稳定性研究及灾害预测提供理论依据。

RESEARCH OF AVALANCHE DISASTER NUMERICAL SIMULATION BASED ON GRANULAR DISCRETE ELEMENT METHOD OF HIGH-STEEP SLOPE UNDER SEISMIC LOADS

Based on analysis of high-steep slope at Jiangping River hydropower project，the block overturning analysis method is used to determine the potential damage zone under seismic loading，and then wave propagation equation and boundary condition equation are derived. The collapse disaster of high-steep slope is studied according to two-dimensional granular flow method. The results show that the stability of slope can be determined by particle trajectories with the collapse hazard analysis of granular discrete element method. Then the path of destruction can be studied. By modifying the properties of boundary particles，the incident seismic wave and transmitting boundary condition can be simulated，so it will maximally simulate the coupling process of loading，rock properties and the development of disaster. It also shows that the development of longitudinal unloading fissures whose dip angle is approximately equal to slope free surface is the controlling factor to the stability of high-steep slope under seismic loads，and local collapse and block instability may occur on the superficial slope. The process of collapse starts from the partial avalanche of surface rock mass when an earthquake occurs，then it extends rapidly along the fissures until it gets up to the upper rock under high-intensity earthquake. The scale of collapse is mainly decided by the depth of development of fissures. Therefore，the proposed method can provide a theoretical basis for the stability study of high-steep slope as well as the disaster prediction.