半胶结中低强度围岩导水裂缝带发育特征研究

为获得半胶结中低强度围岩条件下巨厚浅埋煤层开采导水裂缝带高度及发育特征，以榆神矿区金鸡滩煤矿101工作面与转龙湾煤矿23103工作面为例，分别采用地面钻孔探测(岩芯工程地质编录、冲洗液漏失量观测及钻孔电视系统)与井下探测(钻孔双端封堵测漏法)对采空区上覆岩层导水裂缝带高度及形态进行了现场探查，采用相似材料模拟和数值模拟对不同开采煤层厚度的导水裂缝带演化规律及发育高度进行了研究。根据现场实测和模拟结果，结合其他相似条件的矿井实测数据，对导水裂缝带发育高度与煤层采厚的关系进行了拟合分析。研究表明：大跨度工作面导水裂缝带发育高度与煤层采厚为二项式关系，随采厚增加，导水裂缝带高度增大，但增大趋势变缓；导水裂缝带发育形态为平顶拱形，在工作面推进距离与工作面斜长近于相等时，“裂隙拱”在垂向上不再扩展，此时导水裂缝带高度达到最大。

Study on development characteristic of water flowing fractured zone under semi-cemented medium-low strength country rock

In this paper,the 101 working face in Jinjitan Coal Mine and the 23103 working face in Zhuanlongwan Coal Mine were investigated to study and analyze the development characteristic of water flowing fractured zone under semi-cemented medium-low strength country rock.In the in-situ detection of the height and shape of water flowing fractured zone,ground and underground boreholes were used.Ground drilling detection included rock core geological logging,flush liquid leakage observation and drilling TV system.Double-end seal leakage device was used to take the detection in the underground borehole.Numerical simulation and similar material simulation were employed on the study of the height and evolution of water flowing fractured zone under different mining conditions.Based on the detection and simulation results,and the in-situ detected data in other mines with similar mining condition,the quantitative relationship between the height of water flowing fractured zone and coal seam mining thickness under semi-cemented medium-low strength country rock had been concluded.Research shows that there exists a binomial relationship between the height of water flowing fractured zone and the mining thickness.In the profile across the mining working face,the shape of water flowing fractured zone is raised to be an “arch”.The “fractured arch” extends upward and forward with the working face advancing until the advanced distance approximately equals to the mining face width,the height of water flowing fractured zone at this point reaches its highest point.