Study on coal wall stability and reasonable process parameter in fully mechanized caving face of thick coal seam

The mining pressure in the thick fully mechanized caving face is severe.Reasonable selection of technological parameters can effectively reduce the mining pressure phenomena such as coal wall slicing, roof falling and support pressing.The cutting height, end distance and support working resistance are the main technological parameters affecting the mining pressure phenomenon in the fully mechanized caving face.The stability of coal wall and reasonable technological parameters are studied by theoretical analysis and numerical simulation.The mechanical model of the interaction between the coal wall and the support is established, and the expression of the relationship between the support strength and the cutting height satisfying the stability of the coal wall is obtained.FLAC^3D numerical simulation is used to analyze the influence of different mining and caving ratio and face distance on the stability of face coal wall and top coal in fully mechanized caving mining.The curve of variation of vertical stress, horizontal displacement and leading abutment stress of face coal wall and top coal under different cutting height and face distance is obtained.Comprehensive consideration of coal wall and the stability of the top-coal, bracket supporting strength for the limitation of coal cutting height, to determine the reasonable of fully mechanized caving mining face of coal cutting height is 2.5-3.5 m, end face on top-coal displacement is greater than the influence of coal wall, reduce the transverse distance, strengthened the stability of fully mechanized caving coal, determine reasonable fully mechanized caving face distance less than 250 mm.The research results can provide reference for the optimization of process parameters of fully mechanized caving face under similar conditions.