Deformation mechanism and control technology of secondary mining roadway deformation under shallow buried thick bedrock
Taking the 31302 comprehensive mining face of Jinjie Coal Mine as the research object,using on-site analysis,numerical simulation and other methods to investigate the manifestation law and control technology of strong mining pressure under the secondary mining roadway deformation under the shallow buried thick bedrock roof.The opening cut at the top plate of the 31302 working face is thick and hard,the collapse of the basic roof layer resulted in a weak to strong pressure pattern on the working face during initial mining,the mining pressure on the tail side of the machine is obvious,and the hanging roof of the goaf on the upper section of the coal pillar side is long,the concentrated stress in the coal pillar is high.During the mining process of 31302 working face,20-30 fractures occurred on the tail side of the machine,which causing severe deformation of the surrounding rock of the roadway.The coal seam is relatively fragmented and has developed joints and fissures when the working face passes through the rich water area,when affecting by mining,it is easy to encounter the phenomenon of roof caving,the deeper the caving depth of the coal seam is,the larger the area of the empty roof is,which is prone to roof deformation and collapse accidents.In summary,the paper starts from two aspects,strengthening the support and strengthening the coal pillar strength,and using high-strength advanced supports to reduce the stress caused by the hanging roof of the upper section on the coal pillar,when the top plate is hard,measures such as advanced water pre splitting and anchor retreat must be taken to control the overhanging area,reduce the concentrated stress in the coal pillar,and create conditions for the mining of the lower section working face.
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