煤层压裂卸压防冲机制研究

Study on Pressure Relief and Erosion Prevention Mechanism of Coal Seam Fracturing

针对彬长矿区高地应力厚煤层开采时冲击动力灾害严重问题,采用理论分析和现场试验等方法,对压裂煤层卸压防冲机制进行了研究。研究表明:煤层压裂破碎后,煤体裂纹扩展表面能降低,产生碎块数量增多,耗散能占比越大,可释放弹性能减小;煤层压裂区应力存在往非压裂区转移现象,巷道侧煤体由压裂前的塑性-弹性2区变为压裂后的塑性-弹性-塑性-弹性4区分布;压裂煤层裂隙发育,应力集中系数降低,塑性区范围显著扩大,煤体弹性能得到释放,有效地预防了冲击地压的发生。

In view of the serious problem of impact dynamic disaster in the mining of high stress thick coal seam in Binchang mining area, the pressure relief and erosion prevention mechanism of fractured coal seam is studied by means of theoretical analysis and field test. The results show that after coal fracturing, the surface energy of coal crack propagation decreases, the number of fragments is large, the larger the proportion of dissipated energy is, and the released elastic energy decreases. The stress in the fractured area of coal seam transfers to the non fractured area, and the coal body on the roadway side changes from the plastic elastic area before fracturing to the plastic elastic plastic elastic area after fracturing. The fracture of fractured coal seam is developed, the stress concentration factor is reduced,the range of plastic zone is significantly expanded, and the elastic energy of coal body is released,which effectively prevents the occurrence of rockburst.