Study On Reasonable Layout For The Water Draining Tunnel Under Goaf Of Closed Coal Seam

China's coal resources are abundant,coal deposits are different,and geological conditions vary widely.Most of the mines have different geological conditions and contiguous seams mining.It is an important direction for future development to study the mining of contiguous seams under goaf.In this paper,based on the layout of the water draining tunnel in the East mining area of the Changyuhe Coal.Theoretical analysis,numerical simulation and engineering practice are mainly used for analysis and research.The results are as follows:(1)According to the actual distribution of the water in the east area and buried depth of coal seam,the suitable area of the draining tunnel is determined,and the suitable layer of the water draining tunnel in 15 coal is determined through the distribution of the stress.(2)The drift layout is analyzed about the influence on the imbalance of the stress distribution under the coal pillar,According to the function of the draining tunnel and the utilization of the resources,the reasonable arrangement of he draining tunnel under the goaf of closed coal seam is put forward: The outer way of the draining tunnel is used in the lower coal seam.Based on the theory of mechanics and the analysis of the stability and waterproof effect,the feasibility of the width of the coal pillar between the draining tunnel and the adjacent main roadway is verified.(3)The finite element numerical simulation is used to study the deformation of the roadway between the draining tunnel and the upper goaf at different distances,and the best distance is determined.When the distance between the draining tunnel and the upper goaf is fixed,the numerical simulation of first coalface worked is carried out to verify that the width of the coal pillar is satisfied.(4)Using the theoretical analysis and numerical simulation,the space location and parameters of the draining tunnel are determined in the mined out area under the near coal seam.The draining tunnel is located in the lower 15 coal seam and the upper 15101 goaf;The lower seam draining tunnel should be adopted outside type layout,and the upper goaf outside 10m;According to the analysis and simulation of the stable state and the waterproof effect,the 28 m coal pillar in the adjacent main roadway can ensure the strength and stability.According to the theoretical analysis and engineering application,to some extent,some problems are explained about the reasonable distance between the draining tunnel and the upper goaf,and the reasonable coal pillar width of the tunnel adjacent to the closed coal seam,which provide some reference for the engineering under the same kind of geological strip.