Study On Development Height Of Water Flowing Fractured Zone In Fully Mechanized Top Coal Caving Mining Of Xindeng Coal Mine

After coal mining,the stress balance of the original rock is destroyed,resulting in a series of evolution of the rock stratum and the formation of water diversion fracture zone,which brings major hidden dangers to the safety production of coal mine.Therefore,the research on the development height of water diversion fracture zone is of great significance to prevent water disaster accidents in coal mines.Taking 31101 working face of Xindeng coal mine as the research object,this paper comprehensively applies the methods of theoretical analysis,physical similarity simulation and field measurement to study the development height of water conducting fracture zone in mining roof and floor of coal seam.Based on the occurrence characteristics of regional coal and rock strata,the development height of water conducting fracture zone of No.21 coal seam in the mine is analyzed and calculated through empirical formula.It is obtained that when the coal thickness is 5.2m,the height of water conducting fracture zone of roof is 58.1m and 62 m respectively.When the coal thickness is 9m,the height of roof water diversion fracture zone is 85.80 m and 100 m respectively.The height range of the water conducting fissure zone of the bottom plate is 16.7m～ 17.7m.The physical similarity simulation test is used to reveal the fracture characteristics of overburden and the evolution process of water conducting fracture zone in goaf.Using the method of water plugging at both ends of the borehole and water injection leakage in sections,it is measured that the development height of the water conducting fracture zone in the roof of the mining strata of 31101 working face is 53.58 m ～ 74.24 m,and the height of the water conducting fracture zone in the floor is 5.6m.The development height of roof water conducting fracture zone observed by borehole TV imager is 54.08 m.Based on the research results of the above methods,it is concluded that after the mining of 31101 working face in Xindeng coal mine,the height of the water conducting fracture zone in the roof of the coal seam is 49.2～ 55.6 m and the height of the water conducting fracture zone in the floor is 5.6 m.The research results have important reference value for safe and efficient production,water disaster prevention and reasonable design of waterproof coal and rock pillars in Xindeng coal mine.