Study On The Law Of Overburden Migration Under The Gully Terrain In 85212 Working Face Of Sandaogou Coal Mine

There is an inevitable contradiction between the economic benefits brought by coal mining and the environmental problems caused by mining.Sandaogou coal mine,a modern coal mine in Yulin,Shaanxi Province,is rich in coal resources and has good economic benefits.However,the development of surface fissures and the decline of shallow water level caused by underground mining have seriously damaged the living environment of vegetation in the reserve.It is of positive significance to carry out the basic research on the mining overburden migration and the development law of mining fissures in order to solve the problem of vegetation protection in ecologically fragile mining areas.Therefore,through field investigation,theoretical calculation,physical simulation,numerical simulation,field measurement and other research methods,the overburden migration law under the gully terrain of 85212 working face in Sandaogou coal mine is studied.This paper contains the following results:(1)Based on the mining geological characteristics of Sandaogou coal mine,the key stratum position of 85212 working face is analyzed by the critical layer discrimination software.(2)The influence of slope angle,slope height and mining height on the development characteristics of surface fissures in gully terrain is analyzed.It is found that the opening degree of slope fissures and step subsidence are obviously larger when the working face is pushed back to the gully,while the fissures are smaller when the working face is pushed towards the gully.When the slope angle is less than 30 °,the slope height is greater than 127 m or the mining height is greater than 5m,the mining face has a greater impact on the slope surface fissures.(3)Based on the method of predicting the development height of water-conducting fissure zone by the location of key stratum,it is concluded that the primary key stratum of 85212 working face in Sandaogou coal mine is within 8 times of mining height,and the development height of water-conducting fissure zone in the working face is predicted to reach the top interface of bedrock,which is verified by physical simulation results.The influence of different slope mining conditions on the development height of water-conducting fissure zone is revealed.(4)Green mining technology based on slope fissures control in the gully terrain is proposed,including slicing mining technology,rapid mining technology and filling mining technology.Numerical simulation method is used to analyze the effect of three kinds of technology to control slope fissures,which provides reference for solving the problem of vegetation protection in ecologically fragile mining area.This paper contains 57 figures,11 tables and 98 references.