近直立特厚两煤层同采冲击地压机理及防治

Rock-burst mechanism and prevention in mining sub-erect and extremely-thick coal seam with horizontal slicing method

针对急倾斜特厚煤层特殊的赋存条件和开采技术条件,基于区域构造应力特征和地应力实测结果,建立了急倾斜特厚煤层水平分段开采两侧采空岩柱的外伸梁力学模型,分析得到了近直立特厚水平分段两煤层同采条件下两侧采空岩柱对煤体的"撬杆效应"构成了冲击地压的力源并获得其表达式,提出了由于该力源作用在煤体上产生的应力随时间的变化率达到或超过煤体的动态破坏应力指数而发生冲击地压的致灾机理。数值模拟结果和现场微震统计结果表明,主要受水平构造应力影响下的两侧采空岩柱在开采水平以下出现了应力集中和能量集中区域。据此提出了在开采水平超前工作面定期通过爆破和高压注水降低岩柱应力集中程度进行冲击地压解危,效果检验表明防治效果显著。

Occurrence condition and mining method of steeply-inclined and extremely-thick coal seam is very special.On the basis of regional tectonic stress analysis and geo-stress test results,overhanging beam mechanical model of rock pillar between mined two steeply-inclined and extremely-thick coal seams was set up. Force source which might result in rock burst was analyzed and its expression was obtained by mechanical model solution.'Crowbar effect'of rock pillar was put forward to explain coal rock-burst at and below mining level. Numerical simulation and micro-seismic observation results show that stress concentration and energy concentration area occurr below mining level. A rock-burst prevention projection of combining blasting and water-injecting with high pressure was presented to reduce rock-wall stress concentration degree,field application shows good effect.