基于动静错位结合方式的首采工作面覆岩裂缝发育探测研究

Research on Detection of Overburden Fracture Development in the First Mining Face Based on the Combination of Dynamic and Static Dislocation

为研究首采工作面回采前中后期覆岩裂缝发育状态,以发耳煤矿50105工作面为例,提出了动静错位结合的裂隙探测方法。采用覆岩移动曲线与经验公式理论分析,用离散元UDEC软件仿真开挖,用网络并行电法与钻孔摄像法在不同位置现场实测,分析覆岩裂缝发育过程与最终稳定高度。结果表明:工作面前端未采区域超前应力裂缝开始发育,覆岩离层阶段出现裂缝急剧位移差现象;煤层上方主覆盖层为含碎石粉质黏土,覆岩稳定性差,裂缝发育实测高度大于理论高度;在采空区稳定区域,含碎石粉质黏土覆盖层重新压实,顶部裂缝发生闭合,裂缝实测高度降低。研究成果对首采工作面粉质黏土覆岩裂缝发育有新的认识。

In order to study the development state of overburden fractures in the first mining face at the early, middle and late mining stages, taking 50105 working face of Faer coal mine as an example, a fracture detection method combining dynamic and static dislocation was proposed. Based on the theoretical analysis of overburden movement curve and empirical formula, the excavation was simulated by UDEC software, the field measurement was carried out at different positions by using network parallel electrical method and borehole camera method, and the development process of overburden fractures and the final stable height were analyzed. The results show that, the advance stress fractures begin to develop unmined area in the front of the working face, and the rapid displacement difference of the fractures appears in the overburden separation stag. The main overburden in the upper of coal seam is silty clay containing gravel, with poor stability. The measured height of fracture development is higher than the theoretical height. In the stable area of goaf, the silty clay overburden containing gravel is compacted again, the top fracture is closed, and the measured height of fracture is reduced. The research results have a new understanding on the development of fractures in this kind of overlying strata in the first mining face.