Development characteristic of water flowing fractured zone under semi-cemented medium-low strength country rock

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 sim- ulation 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.