大孤山露天矿边坡爆破动力响应与稳定性研究

Study on dynamic response and stability of slope blasting in Dagushan Open-pit Mine

以大孤山露天铁矿为研究对象,利用有限差分软件FLAC^(3D)从速度、加速度和位移3个方面进行了爆破作用下边坡动力响应的数值模拟,并对多次爆破作用下的边坡塑性区、位移和安全系数演化规律进行了分析。研究结果表明:坡面监测点振速出现了高程放大效应,而加速度虽然没有出现明显的高程放大效应,但也出现了加速度衰减变缓的现象;无论是坡面还是坡内,监测点的峰值位移随爆距的增大而逐渐减小,但坡面监测点峰值位移存在局部放大效应;随着爆破次数的增加,位移变化区域和塑性区面积不断增大,安全系数逐渐减小,边坡稳定性逐渐劣化,并在爆破40次之后边坡发生失稳。

Taking Dagushan Open-pit Iron Mine as the research object,the article carries out the numerical simulation of the dynamic response of the slope under the blasting actionin terms of velocity,acceleration and displacement using the finite difference software FLAC^(3D),and analyzes the evolution law of the plastic zone,displacement and safety coefficient of the slope under the action of multiple blasting.The results show that the vibration velocity of the slope surface monitoring point has an elevation amplification effect,while the acceleration does not have an obvious elevation amplification effect,but also has a phenomenon of slowing down the acceleration decay.Whether on the slope or within the slope,the peak displacement of the monitoring point gradually decreases with the increase of the blasting distance,but the peak displacement of the monitoring point on the slope has a local amplification effect.With the increase of blasting times,the area of displacement change region and plastic zone continuously increases,the safety factor gradually decreases,and the slope stability gradually deteriorates,and the slope becomes unstable after 40 blasts.