急倾斜特厚煤层层间岩柱动力学失稳诱灾倾向预测

Induced hazard-prone prediction to the intermediate rock-pillar dynamic instability in heavy steep-thick coal seam

乌鲁木齐矿区乌东煤矿开采条件复杂,急倾斜煤层群间赋存均厚60m倾斜岩柱,近年来已发生十余次动力灾害。针对急倾斜岩柱动力学失稳诱灾倾向预报,采用开采条件调查、理论分析和现场监测等方法,综合预测了深层岩柱动力学失稳诱灾倾向区域。首先,基于现场调查成果,构建了急倾斜岩柱失稳应力撬转效应(stress leverage rotation effect,SLRE)力学模型,揭示了岩柱动力学失稳诱发动力学灾害的力学机制。再次,通过现场微震监测,分析了岩柱破断失稳微震—能量—空间演化规律:急倾斜岩柱动态失稳经历扰动破裂、应力挤压、断裂失稳和应力重构阶段。最后,综合分析并圈定了深层岩柱动力失稳诱灾倾向区域,其分别位于B1-2煤层+500^+510 m区域开采煤体、B3-6煤层+475^+485 m区域岩柱侧煤体,这为现场灾害防控设计和安全开采提供了科学依据。

There existed 60 m thick and steep rock-pillar at Wudong mine. More than ten dynamic accidents happened in recent years. For prediction on dynamic destabilization and induced hazard-prone to interlayer steep rock pillar,some methods using in-situ mining condition investigation,theoretical analysis and field monitoring were achieved. The induced hazard-prone was predicted of the deeper rock-mass damage and dynamic instability of heavy steep-thick rock pillar. Firstly,the mechanical model on stress leverage rotation-effect（ SLRE） was built based on in-situ mining condition investigation,and the mechanism of induced hazard was analyzed. Then,according to the field monitoring and analysis,we indicated that the spatial distribution and its evolutionary law of micro-seismic energy releasing of rock pillar and hazard-prone zone. The steep pillar dynamic destabilization related to disturbance burst,stress squeezing,damage destabilization and stress redistribution. Finally,the induced hazard-prone region and ranging under SLRE have been determined,respectively,locating coal excavated from ＋ 500 ~ ＋ 510 m of B1- 2and coal neighboring rock pillar to ＋ 475 ~ ＋ 485 m of B3- 6. This provides a scientific proof for hazard control and safe mining.