深部掘进巷道爆破卸压防治冲击地压技术

针对深部掘进巷道采用大直径钻孔卸压防治冲击地压存在卸压强度低、卸压不及时、劳动强度大等问题,以陕西彬长矿区孟村煤矿401103回撤通道为工程背景,分析了冲击地压发生主控因素,认为煤岩层强冲击倾向性、大埋深、断层构造是诱发冲击地压的主要原因:煤岩层具有强冲击倾向性使得煤岩系统具备发生冲击地压的能力;工作面埋深大导致集中静载荷水平处于高位,降低了冲击地压发生门槛;主承载区高集中静载荷叠加断层能量积聚释放的集中动载荷,极易诱发冲击启动,进而导致冲击地压显现。利用爆破卸压防治冲击地压作用表现为结构重建、应力释放及能量消耗:对掘进巷道围岩支承压力峰值区域实施爆破致裂可在巷道围岩内形成卸压保护带,从而降低煤岩冲击倾向性、削弱高集中应力、增加冲击能量消耗,达到降低冲击地压风险的目的。针对401103回撤通道提出了顶板、掘进工作面、帮部爆破卸压方案,并采用震波CT探测及微震监测对卸压防冲效果进行检验,结果表明:采用爆破卸压方案后,高应力区面积减少了50%,应力集中程度明显降低;微震事件平均能量显著下降,均小于10⁴ J,且微震事件能量无急剧变化,卸压效果良好。

Blasting pressure relief technology for preventing rock burst in deep heading roadway

In order to solve the problems of low pressure relief intensity,untimely pressure relief and high labor intensity in the prevention and control of rock burst by using large diameter borehole pressure relief in deep heading roadway,taking the 401103 withdrawal roadway of Mengcun Coal Mine in Binchang mining area of Shaanxi Province as the engineering background,the main control factors of rock burst are analyzed.It is considered that the strong rock burst tendency,large buried depth and fault structure of coal and rock layers are the main reasons of rock burst.Coal and rock layers have strong rock burst tendency,which makes the coal rock system capable of generating rock burst.The large buried depth of the working face leads to a high level of concentrated static load,which reduces the threshold for rock burst.The high concentrated static load in the main bearing area superimposes the concentrated dynamic load released by fault energy accumulation,which can easily induce shock start and lead to the appearance of rock burst.The use of blasting pressure relief to prevent rock burst is manifested in structural reconstruction,stress release and energy consumption.The implementation of blasting cracking in the peak area of the supporting pressure of the surrounding rock of the heading roadway can form a pressure relief protection zone in the surrounding rock of the roadway,thereby reducing the tendency of coal rock burst,weakening high concentrated stress,increasing rock burst energy consumption and reducing the risk of rock burst.For the 401103 withdrawal roadway,the blasting pressure relief scheme of roof,heading face and side are proposed.And the effect of pressure relief and anti-rock burst is tested by seismic wave CT detection and micro-seismic monitoring.The results show that after adopting the blasting pressure relief scheme,the area of the high stress area is reduced by 50%,and the stress concentration is significantly reduced.The average energy of microseismic events is significantly reduced,the energy is all less than 10⁴ J.And there is no sharp change in the energy of microseismic events and the pressure relief effect is good.