深部煤层开采导水裂隙发育规律研究

Study on Development Patterns of Water-conducting Fractures in Deep Coal Seam Mining

导水裂隙发育规律是深部煤层安全开采的一个重要参数,以孔庄煤矿7303工作面为依托,采用相似模拟实验、钻孔注水漏失量探测和钻孔窥视相结合的方法,对工作面导水裂隙发育特征进行研究。结果表明:相似模拟实验表明工作面平均周期来压步距19.5 m,垮落带呈梯形,随着工作面推进,离层裂隙被压实,导水裂隙发育由低速向高速转变,导水裂隙最大发育高度69.8 m,裂采比21.8。通过现场实测得到导水裂隙最大发育高度65.27 m,裂采比18.13,与浅部煤层工作面裂隙发育特征进行对比分析,裂采比与煤层埋深呈正相关。该研究成果对孔庄煤矿防治水害具有重要的指导意义。

The development pattern of water-conducting fractures is an important parameter for the safe mining of deep coal seams.Based on the 7303 working face of Kongzhuang coal mine,a combination of similar simulation experiments,borehole water injection and leakage detection,and borehole visual inspection methods were used to study the characteristics of water-conducting fracture development in the working face.The results show that in the similar simulation experiments,the average periodic overburden distance of the working face is 19.5 m.The roof of the working face undergoes strata separation,fractures,and collapse,forming a trapezoidal subsidence zone.As the working face advances,the strata separation fractures gradually become compacted,and the development of water-conducting fractures transitions from low speed to high speed.The maximum development height of water-conducting fractures is 69.8 m,with a fracture-to-mining ratio of 21.8.Through on-site measurements,the maximum development height of water-conducting fractures is found to be 65.27 m,with a fracture-to-mining ratio of 18.13.A comparison with shallow coal seam working faces indicates a positive correlation between the fracture-to-mining ratio and the depth of the coal seam.This research outcome has significant implications for water hazard prevention in Kongzhuang coal mine.