Optimization study on pressure relief gateway layout for fully-mechanized top coal caving mining with gateway driven along goaf

In order to solve difficult problems of serious mine strata behavior and serious deformation occurred in the gateway driven along the goaf during fully me chanized top coal caving mining process with small coal pillar gateway driven along the goaf, the pressure relief gateway layout method in mining seam was applied to surrounding rock control of the gateway driven along the goaf.The numerical simulation method was applied to study pressure relief gateway in layer location of thick se am, the central distance between pressure relief gateway and gateway retained along goaf and the dimension of pressure relief gateway factors affected to pressure rel ief effect of the pressure relief gateway.An optimization was conducted on the layout method of the pressure relief gateway.The results showed that layout of pressure「 elief gateway could reduce stress concentration coefficient of solid coal, and area of stress concentration block, could make stress concentration moving forward to dee p section of the seam and could reduce the surrounding rock stress of the gateway retained along the goaf.The best optimized layout method of pressure relief gateway was that pressure relief gateway should have a ripping layout in thick seam, the center distance of pressure relief gateway would be 2.7 ~ 3.2 times of width of gateway retained along the goaf and size of pressure relief gateway should be the same as gateway retained along the goaf.The layout method was applied to mine site with exc ellent technical and economic benefits.