益新矿中心大空孔掏槽爆破扩腔过程数值分析

为了更好的应用中心大空孔掏槽爆破技术,根据益新煤矿爆破工况,运用有限元软件LS-DYNA,深入分析爆破过程中应力波的传播、有效应力和应力场的变化,研究其扩腔过程及岩石破碎机理。结果表明:爆炸应力波首先在炮孔连线方向相遇叠加并形成一条直线型的加强带,然后传至空孔并发生复杂的反射和叠加,最后在岩体中扩散;空孔外围的应力场分布呈现"圆形-菱形-圆形-方形"的变化规律;中心大空孔掏槽爆破有利于炸药能量的均匀分布和槽腔的形成与扩展。现场验证表明:该项技术大大提高了煤矿巷道的掘进速度,取得了较好的经济效益。

Numerical Analysis on Expansion Chamber Process of Large Hollow Hole Cut Blasting in Yixin Coal Mine

In order to improve the technology of large hollow hole cut blasting,according to the Yixin coal mine blasting conditions,the finite element analysis software LS-DYNA was used to study the process of expansion chamber and rock breaking mechanism,and to analyze the stress wave spread and changes in effective stress and stress field.The results show that the stress wave of large hollow bore parallel cut meets and forms a linear reinforcing tape in boreholes connection direction,and then spreads towards the hole.Followed by complex superposition and reflection,the stresses diffused in rock finally.The surrounding stress field on large hollow bore presents "round-diamond-round-square" pattern.The parallel cut blasting of large hollow bore is in favor of explosive energy distribution,the formation and expansion of the groove cavity.The field verification shows that the technology greatly improves the tunneling speed of coal mine and achieves good economic benefits.