利用微震监测及现场冲击记录,对冲击震源、能量、显现区、显现范围及显现形式等进行定位与统计分析,总结冲击特征。通过理论建模与计算,从围岩体结构和应力状态2方面分析孤岛煤柱冲击机制。研究表明:60 m厚基本顶不破断及临空区覆岩“二次”运动使冲击震源均分布在临空区及其边沿;随孤岛面推进,煤体静载应力峰值逐渐增高并接近冲击临界应力,高静载应力与动载应力叠加达到并超过冲击临界应力使冲击频发;两巷靠近设计停采线部分为静载应力峰值区,该段巷道底板距15-3煤0~1 m,使该段巷道成为重复冲击显现区;机道应力高于风道,使机道显现次数多于风道,分别为6次和3次;巷道底板无支护,接近15-3煤,使显现形式主要为底鼓。该分析方法与思路为类似条件下的冲击治理提供借鉴。
Using microseismic monitoring and rock burst records, the burst source, burst energy, dam-age area, damage scope and damage form etc. were located and analyzed statistically in this paper, and rock burst characteristics were summarized. Meanwhile, by means of theoretical modeling and calcula-tion, rock burst mechanism in island pillar coalface was analyzed from the aspects of rock mass struc-ture and stress state. The results show that all the burst sources are located at the adjacent gob and its edge due to the no breaking of the 60-meter-thick main roof and the secondary-movement of the adja-cent gob overburden.With the coalface advancing, the maximum static stress within coal mass rises gradually and comes close to the critical stress. Thus, the superposition of such a high static stress and dynamic stress reaches the critical stress for rock burst, leading to frequent occurrence of rock burst. Both gateways near the designed ending line are the maximum static stress locating area. With a 0-1 m distance between the gateway floor and No.15-3 coal seam, this area has been damaged repeatedly when rock burst occurred. Because of a higher static stress, the headgate has been damaged 6 times, 3 times more than that of the tailgate. The main damage form of the gateway is floor heaving since the floor is without support and the distance between the floor and coal seam is small. The analysis in this paper may provide a reference to rock burst control with similar conditions.