弱固结地层特厚煤层综放开采覆岩破坏及水害防控研究

Study on overburden failure characteristics and water disaster prevention and control technology in fully mechanized extra thick coal seam in weak consolidated strata

为解决多重含水层下弱固结特厚煤层水害防治问题,本文采用类比分析法、数值模拟法和相似模拟法,研究了灵东煤矿采空区下Ⅱ3特厚煤层顶分层开采的覆岩破坏特征,分析了导水裂缝带发育特征,提出了“物探+钻探”的方式提前疏放导水裂缝带内含水层的控水采煤方法。研究结果表明,位于Ⅱ3特厚煤层上覆的Ⅱ2特厚煤层回采时,覆岩破坏呈现“阶梯式”垮塌特征,Ⅱ3特厚煤层顶分层回采时,在工作面初次来压后,覆岩呈现出与Ⅱ2-1煤层层间岩层同步协调弯曲下沉的现象;预计导水裂缝带未波及Ⅱ2-1煤层采空区,采用“音频电透视+瞬变电磁”探测得出一含、二含(1)的采空区的富水异常区,重点针对富水异常区进行钻孔探测,兼顾非富水异常区,最终实现了首采工作面的安全回采。

In order to solve the problem of water disaster prevention and control in weakly consolidated extra thick coal seam under multiple aquifers,by using analogy analysis method,numerical simulation method and similar simulation method,and the overburden failure characteristics of layered mining in the top ofⅡ3 extra thick coal seam under the goaf of Lingdong Coal Mine are studied,and the development characteristics of water conducting fracture zone are analyzed.The method of“geophysical prospecting+drilling”is put forward to release the aquifer in the water conducting fracture zone in advance.The research results show that the overburden failure of theⅡ2 extra thick coal seam overlying theⅡ3 extra thick coal seam presents the characteristics of“ladder”collapse during mining.When the roof of theⅡ3 extra thick coal seam is mined in layers,the overburden presents the phenomenon of bending and sinking in coordination with the interlayer strata of theⅡ2-1 coal seam after the first pressure of the working face.It is estimated that the water conducting fracture zone has not affected the goaf of coal seamⅡ2-1.The“audio frequency electric perspective and transient electromagnetic”is used to detect the water rich abnormal area containing water in goaf Yihan and Erhan(1).The drilling detection is focused on the water rich abnormal area,taking into account the non-water rich abnormal area,and finally the safe mining of the first mining face is realized.