影响冲击地压危险性评价结果的Ⅱ类开采技术因素研究

Study of Ⅱ class mining technical factors influencing results of pre-assessment of rockburst risk

针对目前冲击危险性评价方法的不足,提出了II类开采技术因素,并揭示了该类因素诱发煤岩震动异常并激发灾害发生的内在规律。结果表明,工作面推进度与高能震动事件频率成正比,推进度变化梯度与高能震动事件能量大小成正比,大的变化梯度将增加冲击地压突发的风险;煤层卸压爆破针对巷道两帮冲击启动区,爆破后7~18 h内是解危措施发挥作用的主要时段;巷帮扩修使得围岩从原有的相对稳定变为不稳定状态,扩修进尺过快显著影响煤岩震动异常;工作面停产后恢复生产时期,各能级的微震事件急剧上升,且伴随高能事件发生的危险。II类开采技术因素临时介入,打破原有平衡状态,使得煤岩宏观调整,微观破裂突然无序,激发煤岩冲击事件发生。

To overcome the deficiency of current risk pre-assessment method, the II class mining technical factors are defined and pointed out to reveal how the II class mining technical factors inherently induce the abnormal vibrations of coal and rock, and trigger disasters. The results show that: the greater the rate of face advance mining, coal and rock shake more frequent and the greater probability of the high-energy shock event, To decrease in low-level microseismic events, and high-energy event frequency increased, overall microseismic activity enhancement when the workface with a uneven advance rate, The method of blasting to relief stress in coal seam aimed the burst start-up areas of the roadway's sides, So the energy released of per kg dynamite during blasting much larger than the amount of energy released of blasting in roof or ground; the 7-18 h is the most effective period of dangerous lift. The original balance of stress field were broken by the repair in roadway's sides; the wall rock from a relatively stable state becomes unstable; the greater the rate of repair in roadway's sides, and the greater probability of the high-energy shock event. A sharp rise in the various levels of microseismic events, and the risk associated with high-energy events because of the ceasing and recovery production of workface. II class mining technology factors temporary intervention, breaking the original balance state, make coal rock macro adjustment, micro fracture suddenly disorder, stimulate coal rock impact events occur.