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在深部岩石的破碎中,深孔爆破具有高效安全的特点,为改善爆破效果,使岩体的完整性降低,采用空孔控制裂纹的扩展,同时利用空孔补偿岩石的位移。根据爆破理论,确定压碎区、裂隙区、弹性区的范围,通过实验研究空孔位于不同作用区时岩石的断裂方向,分析空孔与装药孔间的距离对裂纹扩展的影响,并测量不同孔间距时空孔周围的应变。实验结果表明,空孔位于爆破裂隙区时,可以有效控制裂纹的扩展方向,空孔有定向致裂的作用,此时空孔周围的应变最大。在淮北矿业集团煤矿顶板弱化中,合理布置爆破参数,使难冒顶板变为易冒顶板,爆破后岩体声速降低40%~50%,爆破区域裂纹扩展,工作面推进阻力降低,达到爆破设计要求,提高了生产效率。
In the deep rock crushing, deep-hole blasting has the characteristics of high efficiency and safety. In order to improve the blasting effect and reduce the integrity of the rock mass, pores are used to control the expansion of the crack while the displacement of the rock is compensated by the void. According to blasting theory, the range of crushed zone, cracked zone and elastic zone is determined. The fracture direction of the rock when the holes are located in different action zones is experimentally studied, and the influence of the distance between the holes and the charge holes on the crack propagation is analyzed and measured Strain around the hole with different hole spacing. Experimental results show that when the hole is located in the blasting fracture zone, the crack propagation direction can be effectively controlled and the hole has the function of directional fracture. At this time, the strain around the hole is the largest. In Huaibei Mining Group coal mine roof weakening, blasting parameters are reasonably arranged to make it difficult for the roof to take the roof. The sound velocity of the rock mass after blasting is reduced by 40% ~ 50%, the crack propagation in the blasting area is extended and the propulsion resistance of the working face is reduced, reaching the blasting design Requirements, improve production efficiency.