Protection layer filling mining key parameter design method

The invention relates to a protection layer filling mining key parameter design method, which is suitable for the gas pressure relief problem of a close-range coal seam group, and comprises the following steps: step 1, according to the thickness, interlayer spacing and gas content of each coal seam in the close-range coal seam group, the position of a protection layer and the position of a protected layer are preliminarily selected, and the protection layer is an upper protection layer; 2, on the basis of the actual geological conditions and coal rock parameters of the selected protective layer and the protected layer, solving the length x0 of a corresponding coal seam yield area when the interlayer spacing is the maximum plastic failure depth hmax of a floor rock mass, determining the equivalent mining thickness hd, calculating the final height hc of a filling body, and forming a protective layer filling mining key parameter calculation model; and step 3, using numerical simulation software to monitor and ch