Study on equivalent calculation method of surface subsidence in inclined coal seam mining

At present,the calculation of surface movement and deformation caused by inclined coal seam mining is generally equivalent to the seminfinite superpo sition of two horizontal coal seams or the horizontal division of inclined coal seams. The calculation process is too simplified. In order to overcome the error caused by t he simplified calculation of the inclined coal seam mining,this author put forward the calculation of the relative position relationship between the surface point and the in clined coal seam to convert the equivalent horizontal coal seam using the mining influence angle,and converts the calculation of the movement deformation of the inclin ed coal seam into the horizontal coal seam calculation. An equivalent calculation method for surface movement deformation in inclined coal seam mining was proposed, and the equivalent calculation results with the calculation results of semi-infinite superposition mining and horizontal division were compared,and the reasons for the cal culation errors of semi-infinite superposition and horizontal division simplified calculation were analyzed. The research results show that:①The equivalent calculation 「 esult is basically the same as the calculation result of the semi-infinite mining superimposed subsidence value. The error in the deformation calculation is manifested in the semi-infinite mining superimposed calculation of the same tensile and compression deformation values on both sides of the upper and lower boundaries,falling to ful ly reflect the close relationship between deformation and mining depth;②Due to the influence of the coal seam dip and the propagation angle of mining influence,the ca Iculation error of the subsidence value and horizontal deformation value of the horizontal division method is larger. The larger the coal seam dip,the greater the error. T his error will not be eliminated due to the increase in the number of horizontal coal seams;③The equivalent calculation method can eliminate the simplified error of the probability integral method in the calculation of the surface movement and deformation of the inclined coal seam mining,and achieve a perfect fit between the calculatio n results and the theory. The research results can enrich the mining subsidence prediction system and have certain significance for improving the calculation accuracy of surface movement and deformation in inclined coal seam mining.