基于岩粉分段装药的爆破技术研究

Study on blasting technique based on rock powder deck charge

采用LS-DYNA动力有限元分析程序,模拟计算了深孔台阶爆破条件下炮孔连续装药和采用岩粉作为间隔介质的分段装药爆破效果。对比分析了连续装药和三种不同分段比例的装药结构爆炸后孔壁的压力极值和压力衰减程度,以及通过Von Mises有效应力极值判别自由面单元是否发生破坏。计算表明,炮孔上部装药40%,下部装药60%,中间采用岩粉作为间隔介质的分段装药结构能够提高炸药能量的利用率,更有利于中上部岩石的破碎。通过对青海威斯特铜矿的爆破试验,进一步验证采用岩粉作为间隔介质的分段装药结构不仅可以降低大块率和爆破振动强度,同时还能够减少爆破综合成本。

The simulations are performed to analyze the effect of continuous charge and deck charge structure in bench blasting by using LS-DYNA program. There are four types of charge structures in this paper including one kind of continuous charge strueture and three kinds of deck eharge structures with different charge ratios. The results obtained from the simulation are used to make comparison including the peak pressure and pressure attenuation against the borehole. At the meantime, the Yon Mises yield criterion is used to judge whether the damage have occurred or not in the free surface elements. It is shown that the method which charged with 40% upper, 60% lower and the rock powder in the middle can improve the utilization of explosive energy efficiently. Besides, the result shows that it is also benefit for upper rock crushing. In addition, the blasting test in West Copper Mine shows that this kind of deck charge structure can not only decrease the boulder Yield and blasting vibration sharply hut also reduce the overall cost of blasting effectively.