【摘要】 针对露天矿开采过程中,爆破开挖作业对最终边坡稳定的影响问题,采用动力有限元法分析爆破过程中边坡的稳定性随时间变化情况。首先建立矿山边坡的二维有限元模型,利用有限元强度折减法求解,得到边坡的最危险滑动面及折减安全系数;再根据得到的最危险滑动面,重新建立边坡和炸药的三维实体模型,布置爆破孔网参数并设置各个炮孔的起爆时间,通过LS-DYNA大型动力有限元程序,求解边坡在炸药爆炸后30 s时间内的动力响应过程。结合极限平衡法和动力有限元法计算结果,计算边坡在同时起爆方式下每一时刻的安全系数。提出应根据边坡时程安全系数及边坡滑面单元是否同时发生整体破坏等条件综合评价边坡稳定性。数值模拟结果能够动态显示爆破过程中边坡的应力、应变状态,计算结果与极限平衡法计算结果接近,可以为露天矿爆破设计提供参考。更多还原

【Abstract】 For the significant impact of blasting on slope stability during open-pit mining process,the dynamic finite element method is used to analyze the variation of slope stability with the time in blasting. Firstly,the finite element model of mine slope is established,then the finite element strength reduction method is adopted to get the most dangerous sliding surface and safety coefficient of the slope. After that,based on the most dangerous sliding surface obtained,a three-dimensional entity model of slope and explosives was created,the blasting parameters are arranged and the initiation time for each hole is set up. Next,this model is calculated after the initiation. The dynamic response process after slope explosive for 30 s is solved by LS-DYNA large dynamic finite element program. Combining with the limit equilibrium method and dynamic finite element method,the safety factors of slope at every moment under unified detonation are calculated. Slope stability should be comprehensively evaluated by the time-history safety coefficient and whether the elements of the sliding surface are destroyed at the same time. The simulation results can dynamically display the security status of slope blasting process,and the result is very close to that by the limit equilibrium method. This research could make a reference for the blasting design.更多还原