预裂爆破弱化坚硬顶板技术在沿空留巷的应用

摘要

It is hard to apply the general gob-side entry retaining technology due to the larger mining depth and many working faces with hard roof in Jixian Coal Mine. In order to solve the problem caused by large and long time hanging roof,large surrounding rock stress concentration on the condition of using gob-side entry retaining in hard roof,the pre-splitting blasting technology in weakening hard roof was adopted in No. 2 mining area of western Jixian Coal Mine to weaken the roof and to reduce the length of hanging roof,finally the impact of motion of hard roof on the artificial side got decreased. The results showed that after surrounding-rock movement of gob-side entry tended to be stable,the tunnel roof convergence was much less than that of the general gob-side entry retaining and the load of ar-tificial side was less than the bearing capacity of artificial side. As a result,the gob-side entry was stable enough.%集贤煤矿开采深度大,多为坚硬顶板工作面,使得普通沿空留巷技术难以有效实施.为了解决沿空留巷工作面基本顶悬顶长度大、时间长,应力集中程度高的问题,在西二采区二片下料道采用预裂爆破弱化坚硬基本顶技术提前预裂基本顶,弱化顶板,减小基本顶悬顶距,降低基本顶运动对人造帮的影响.结果表明:沿空巷道围岩运动趋于稳定后,巷道围岩变形量远低于普通沿空留巷,同时巷旁人造帮所受载荷也低于人造帮承载能力,确保了沿空巷道的稳定性.