孤岛工作面钻孔卸压效果研究及实践

Research and practice on pressure relief effect ofdrilling in island working face

针对孤岛工作面巷道围岩高应力场极易引发局部冲击地压灾害的问题,以陕西煤业龙华煤矿N1206掘进工作面为工程背景,利用FLAC3D建立数值模型,模拟了受动压影响巷道采用钻孔卸压防治冲击地压时,不同钻孔深度和不同钻孔间距下的钻孔周围应力分布情况。根据模拟结果初步确定大直径钻孔卸压技术采用单排眼布置方式,钻孔直径为113 mm,钻孔长度为10 m,孔间距为0.7 m。利用选定钻孔参数进行现场钻孔卸压并监测左右两帮围岩应力随时间变化情况,发现不同深度围岩应力变化规律基本一致,且深处应力值大于浅部应力值,所测应力均在巷道正常围岩应力范围内,证明该钻孔卸压方案的合理性,研究成果为动压巷道冲击地压防治提供一定的指导。

Aiming at the problem that the high stress field of the surrounding rock of the island working face can easily cause local rock burst disaster,No.N1206 heading face of Longhua Mine was taken as the engineering background,FLAC3D was used to establish a numerical model to simulate the stress distribution around the borehole with different borehole depths and different borehole spacings when the drilling pressure relief was used to prevent rock burst in the roadway affected by dynamic pressure.According to the simulation results,it was preliminarily determined that the large-diameter drilling pressure relief technology adopted a single-row eye arrangement.The drilling diameter was 113 mm,the drilling length was 10 m,and the borehole spacing was 0.7 m.Using the selected drilling parameters to carry out field drilling pressure relief and monitor the changes of surrounding rock stress with time on the left and right sides,it was found that the stress changes of surrounding rock at different depths were basically the same,and the stress value in the deep was greater than that in the shallow,and finally the surrounding rock stress tended to be stable.This study provided guidance for drilling pressure relief in dynamic pressure roadway under the condition of island working face.