深埋突出煤层深孔控制爆破致裂机理和防突效果研究

Cracking Mechanism of Deeply Buried Coal Seam by Long-hole Controlled Blasting and Coal-gas Outbursts Prevention

基于理论分析和数值模拟,探究深孔控制爆破技术在深埋低透高瓦斯煤层防突方面的适用性。考虑爆炸波、爆生气体、煤层原始瓦斯压力、煤层地应力对裂隙的作用。研究深埋低透高瓦斯煤层深孔控制爆破裂隙的扩展的过程、机理及防突效果。对比了理论分析结果和典型的现场试验结果。得出的结论是,煤层深孔控制爆破致裂,是在爆炸波的动态冲击震裂和爆生气体及煤层瓦斯压力的尖劈压裂作用下共同完成的;深埋高应力煤层深孔控制爆破机理与常规浅孔采掘爆破机理不同;控制孔在高应力煤层中的导裂作用并不显著,其主要起到卸压孔和抽放孔的作用。几个典型的高应力低透突出煤层的工程实践表明,采用深孔控制爆破技术后,均获得良好的增透效果,且均未发生煤与瓦斯突出事故。

The feasibility of long-hole controlled blasting technique on prevention of coal and gas out- bursts in deeply buried coal seam was studied on the basis of theoretical analysis and numerical simulation. The results indicate that the fracturing of coal seam induced by long-hole controlled blasting is the result of coal seam due to the simultaneous actions of blasting wave, explosion gas, coal seam gas pressure and geo- stress, and the fracture mechanism is different from that of normal shallow blasting. It also shows that the directional fracturing effect of controlled hole in deeply buried coal seam is unobvious compared with that of shallow buried coal seam. However, several typical field applications on prevention of coal and gas out-bursts have proved that the long-hole controlled blasting technique can also be adapted to enhance the per- meability of deeply buried low permeable coal seam.