Calculation method and main factor sensitivity analysis of inclined coal floor damage depth

In order to study the sensibility of coal seam floor damage depth from the main factors of the inclined coal seam floor,based on the semi-infinite body theory in elastic mechanics,a mechanical model was established to model the floor damage depth along the inclined direction of coal seam,and the maximum floor mining damaged depth of in- clined coal seam was calculated. Under the project background of stope conditions of Yangcheng Coal Mine,based on the FLAC3D numerical simulation software,and in the way of orthogonal test,a numerical simulation was made to simu- late the characteristics of coal seam floor damage in 3306 working face. Furthermore,this paper made a calculation to the simulated result in the way of matrix analysis and variance components method to identify the sensibility of each factor influencing the depth of coal seam floor damage. Research shows:① with the increase of the propulsive distance of working face,the minimum principal stress value of the floor is more similar to the confined water pressure value,and the equal areas between the minimum horizontal principal stress value and floor confined water pressure value are in continuous expansion and the danger of floor water inrush increases;② the order of each factor that influences floor damage depth as follows:stope width,mining depth,cohesive force,mining thick,coal seam dip angle,hydraulic pres- sure,and internal friction angle. And the variance analysis results show that the order of sensibility of each factor that influences floor damage depth as follows:the apparent factors are stope width,mining depth,and cohesive force. How- ever,the unapparent factors are mining thick,coal seam dip angle,hydraulic pressure,and internal friction angle;③ the optimal scheme of orthogonal simulation experiment test is determined by matrix analysis method,which can effec- tively reduce the danger of floor water inrush with the minimum floor failure depth.