坚硬顶板预裂爆破的数值模拟研究

摘要

In order to determine the weakening scheme of the hard roof of 10-2coal seam in Ciyaogou Mine,the rock multi-borehole blasting model and the blasting model with free faces were built by the LS-DYNA software,which analyzed the damage zones of multi-borehole blasting and the effective stress change rule of blasting around the free faces.The results indicated that the stress wave induced by multi-borehole blasting superimposed between the adjacent two boreholes,that caused the rapid stress in-crease and the rock fracture,also increased the rock damage range.When the blasting borehole was 5 m away from free face,the stress waves reflected and superimposed near the free face,but could not induce rock fracture.Based on the simulation results, the reasonable blasting parameters and the pre-splitting blasting weakening scheme of hard roof were proposed and determined.%为确定磁窑沟矿10-2煤层坚硬顶板弱化方案,运用LS-DYNA动力分析软件分别建立岩体多孔爆破模型、含自由面岩体爆破模型,分析了多孔爆破的破坏区域和爆破在自由面附近的有效应力变化规律,认为多孔爆破产生的应力波在相邻两孔中间叠加,引起应力剧增,使岩体破坏,能增加岩体破坏范围;爆破钻孔距自由面垂直距离5 m 时,应力波在自由面附近反射叠加,但不会导致岩体破坏.根据数值模拟结果,确定了合理的爆破参数,提出了坚硬顶板的预裂爆破弱化方案.