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In order to study the law of pressure relief of upper protective layer mining. Through theoretical analysis and numerical simulation method, studied the distance on the protection layer mining floor stress field evolution and distribution, found a protective layer on the longwall mining goaf bottom coal seam inclination direction is concave, and strike plane was “O” shape of relief ball shell, the pressure relief angle in the cut or end mining line near the corner of the middle bottom is minimum, the scope of protection of coal seam pressure relief effect than on both sides of the pressure relief effect, namely the scope of protection of inclined coal seam central drainage radius than the two larger; in the trend of protected layer pressure relief protection layer mining face lag distance based on this theory, research to guide the protected layer of gas drilling drainage is very important

Study on the Temporal and Spatial Effect of the Relief Pressure of Upper Protective Layer Mining