空气间隔堵塞爆破数值模拟与试验研究

Numerical Simulation and Experimental Study on Air Deck Stemming of Blasting

提出了一种空气间隔堵塞爆破结构改善岩石爆破效果的方式。通过有限元分析软件ANSYS/LS-DYNA建立了连续堵塞和空气间隔堵塞结构模型,计算得到:采用空气间隔堵塞结构,在装药部分孔壁位置应力峰值明显削弱,但在离炮孔中心远区的岩石应力峰值影响不大,说明该结构有利于控制爆源中心的过破碎,减小粉碎区区域;在空气堵塞段,孔壁单元应力峰值均明显降低,但是有效应力作用时间却明显增加,说明该结构对改善该位置岩石爆破效果有一定促进作用。在岩屑堵塞段,受空气间隔的影响,岩屑堵塞单元应力基本按照一个数量级进行衰减,要达到预期效果应至少设计2段空气间隔段。通过在露天台阶爆破试验证明了该堵塞结构改善爆破效果的可行性。

For improving rock blasting effect,a method of air deck stemming structure is presented in this paper.Through the finite element analysis software ANSYS/LS-DYNA,the models of continuous and air deck stemming structure are established,respectively.The calculation results show that the stress peak value is obviously weakened on the charge part of the hole wall.However,it has little effect for the peak value of rock stress at locations far from the hole center.Therefore,the structure is beneficial to control over-crushing in the center of explosion source and reduce the crushing area.Meanwhile,in the air stemming section,the stress peak value of the hole wall element decreases obviously,but the effective stress action time increases dramatically,which indicates that the structure has a promoting effect on improving the rock blasting effect at this position.In the cuttings stemming section,due to the influence of air decks,the stress of cuttings stemming unit attenuates basically according to an order of magnitude.Furthermore,at least 2 air decks should be designed in the stemming structure to achieve the desired effect.The feasibility of improving blasting effect of the stemming structure is proved by experiments of bench blasting.