万利矿区煤层群开采覆岩裂隙发育规律研究

Research on the Process of Fracture Development in Overlying Rocks Under Coal Seams Group Mining in Wanli Mining Area

采用数值模拟软件UDEC建立了万利矿区煤层群采动的数值模型，模拟研究了采动裂隙发育和煤层群采动相互影响的演变过程，分析了3．1煤顶板岩层采动裂隙的发育规律与预计高度．模拟结果显示，5．1煤的采动可引起3．1煤的裂隙高度略有增加，最终发育高度分别为40m，按经验公式预计则为41～50m，经瞬变电磁、钻孔实测的裂隙发育高度为45m。根据导水裂隙带的发育规律，按3．1煤上覆含水层的富水性、隔水层厚度将矿区分为无水区、不可保区、天然可保区、可保区和观察区，并针对可保区进行了相应的保水开采实践。

Numerical model for coal seam group mining in Wanli mining area was built by using the software UDEC, the process of the fractures development and the interaction when mining between the coal seams group were numerically studied, the development rules of the failure of the overlying rock mass was analyzed and its predicting height of 3-1 coal seam determined. The numerical simulation re- sults shows, 5-1 coal seam mining process caused the slightly increased of the overburden fracture height of 3-1 coal seam, and the height of water flowing fractured zone of 3-1 coal seam can reach 40 m. Moreover the height predicted by empirical formula is 41-50 m, and the height measured by transient electromagnetic and drilling is 45 m. Based on the development rules of the failure of the overlying rock mass, the mining area is divided into 5 kinds according to water-rich degree of aquifer and the thickness of water-resistant strata, namely, non water area, non water protection area, natural water protection area, water protection area and observation area. According to water protection area, we put forward a set of water protection techniques, which is applicable for mining practice.