核桃峪煤矿高地应力条件下深孔爆破预裂应用研究

Study on Application of Deep Hole Blasting Presplitting under High Ground Stress in Hetaoyu Coal Mine

深部岩体处于复杂的地应力环境中,深部爆生裂纹的发育是地应力和爆炸载荷共同作用的结果。基于数值软件LS_DYNA建立了“五花眼”爆破计算模型,采用多物质流固耦合计算方法,分析了不同应力场下爆生裂纹动态演化过程,研究了非静水地应力条件下不同主应力方向裂纹长度变化规律。研究结果表明:爆炸载荷及地应力分别对粉碎区、裂隙区的发育起决定性作用,爆破作用初始阶段载荷远高于地应力,粉碎区发育形态、面积几乎不受地应力影响,随爆炸载荷衰减地应力对裂隙区主裂纹的抑制作用逐渐体现;非静水地应力下最大主应力方向裂纹长度扩展明显优于最小主应力方向,因此炮孔沿最大主应力方向布置有利于炮孔间裂纹的连接贯通。最后基于数值模拟分析结果开展了深部矿井2804工作面“五花眼”爆破预裂的工程应用,结果表明高地应力下“五花眼”深孔爆破起到了良好的硬岩致裂效果。

The deep rock mass is in a complex geostress environment,and the development of deep explosive cracks is the result of the joint action of geostress and explosive load.Based on numerical software LS_DYNA established the"Five Flower Hole"blasting calculation model,analyzed the dynamic evolution process of blasting cracks under different stress fields by using the multi material fluid solid coupling calculation method,and studied the change rule of crack length in different principal stress directions under non hydrostatic geostress conditions.The research results show that the explosion load and the geostress play a decisive role in the development of the crushing area and the fracture area respectively.The load is much higher than the geostress at the initial stage of the blasting action.The development shape and area of the crushing area are almost not affected by the geostress,and the inhibition of the geostress on the main crack in the fracture area gradually manifests with the attenuation of the explosion load;Under non hydrostatic geostress,the crack length extension in the direction of maximum principal stress is obviously better than that in the direction of minimum principal stress.Therefore,the arrangement of blastholes along the direction of maximum principal stress is conducive to the connection of cracks between blastholes.Finally,based on the results of numerical simulation analysis,the engineering application of"five hole"blasting presplitting in 2804 working face of deep mine is carried out.The results show that"five hole"deep hole blasting under high ground stress has a good effect of hard rock fracturing.