上分层回采工作面片帮微震时空演化规律研究

Study on temporal and spatial evolution law of microseismin upper layer mining face rib spalling

煤壁片帮的发生可能影响工作面安全回采。基于赵固一矿16111工作面煤壁片帮微震监测数据,研究片帮发生过程的微震事件时空演化规律,得出以下结论:厚煤层上分层回采时,顶板微震事件频次发育较高,除受采动影响外,频次发育受到断层构造、片帮、回采速度等因素影响显著;片帮发生时顶板事件频次增幅大,影响了工作面周期性变化,对顶板影响大,能量释放剧烈,易引发冒顶事故;片帮期间超前影响范围增大,最大值达到152 m,相比其他时段回采范围骤增;可以适当加快工作面推进速度,减少超前集中应力与煤壁间的作用时间,减弱上覆岩层对煤壁的破坏作用,减小片帮发生概率。

The occurrence of coal wall rib spalling might affect the safe mining of working face.Based on the microseismic monitoring data of rib spalling in No.16111 Face of Zhaogu No.1 Mine,the temporal and spatial evolution law of microseismic events in the process of rib spalling was studied.The following conclusions were drawn:when the upper layer of thick coal seam was mined,the frequency of roof microseismic events was high.In addition to the influence of mining,the frequency development was significantly affected by fault structure,rib spalling,mining speed and other factors.When the rib spalling occurred,the frequency of roof events increased greatly,which affected the periodic change of the working face.and had a great influence on the roof.The energy release was violent,which was easy to cause the roof fall accident.During the period of rib spalling,the influence range of advance increased,and the maximum value reached 152 m,which increased sharply compared with other periods.It could appropriately accelerate the advancing speed of the working face,reduce the action time between the advanced concentrated stress and the coal wall,weaken the damage effect of the overlying strata on the coal wall,and reduce the probability of spalling.