坚硬顶板深浅孔组合聚能爆破技术研究及应用

Research of cumulative energy blasting technology with deep and shallow hole combined in hard roof

针对坚硬顶板条件下实施定向预裂聚能爆破技术后存在钻孔浅部裂缝率低、架后悬顶大的难题,通过理论分析、数值模拟及现场监测,提出了深浅孔组合聚能爆破技术。分析了坚硬顶板单一深孔聚能爆破存在的问题,指出优化钻孔布设及爆破参数是提高爆破效果的主要途径。研究了深浅孔组合聚能爆破技术原理,提出了深浅孔组合能量场理论和组合导向孔力学机制。深浅孔爆破时可形成深部和浅部聚能爆破应力场,同时深孔浅部又对浅孔爆破起到了导向孔的效果,最终可形成切顶范围内的预裂面。现场爆破效果监测,孔内裂缝率提高了30%,并得到了顶板压力变化规律。架后顶板及时垮落充填,消除了坚硬顶板的断裂冲击,降低了留巷围岩控制难度。研究成果可为坚硬顶板条件下切顶留巷的定向预裂高效聚能爆破提供参考。

To solve the problems of low crack rate and large overhanging roof after directional presplitting cumulative blasting technology is implemented under the condition of hard roof,through theoretical analysis,numerical simulation and field monitoring,the deep and shallow hole combined cumulative energy blasting technology is proposed.This paper analyzes the problems of single deep hole combined cumulative energy in hard roof,and points out that optimizing the layout of boreholes and blasting parameters is the main way to improve the blasting effect.The technical principle of deep and shallow hole combined cumulative energy blasting is studied,and the theory of combined energy field and mechanical mechanism of combined pilot hole are put forward.During the deep and shallow hole blasting,the stress field of the inner section and the outer part can be formed.At the same time,the outer part of the deep hole can play the role of the pilot hole in the shallow hole blasting,and finally form the presplitting surface within the scope of the roof cutting.Through the monitoring of blasting effect,the crack rate in the hole is increased by 30%,and the variation law of roof pressure is obtained.The roof falling and filling in time can eliminate the fracture impact of hard roof and reduce the difficulty of surrounding rock control.The research results can provide a reference for directional presplitting high-efficiency cumulative energy blasting under the condition of hard roof.