Research On Supporting Techniques Of Mining-entries In Extremely Steeper Thick Coal Seams

Mining-Entries supporting technology is one of the most important research topic in saftymining of extremely steeper thick coal seams. Based on the spacial geography conditions ofJiangou colliery, we utilized the comprehensive monitoring system, including fieldinvestigation, theoretical analysis, field monitoring and numerical simulation, to research themining-entries supporting techniques and the law of roadway deformation of extremelysteeper thick coal seams. The main results was demonstrated as follows:The deformation style of extremely steeper thick coal seam was ceiling subsidence,bilateral astringent;The most serious damages appeared in ceiling; the deformation in southernside was bigger than northern side, the deformation at upper northern side was bigger than thedeformation at southern side. The crucial area which stress of ceiling mining-entries focusedon upper northern side. Mining-entries of deeper panel was influenced by both the excavationin previous sublevel and stress transmission of the spanning strata arch in the followingsublevel, which inducing the superposition in the following sublevel. The conclusion basiclycoincided with the theoretical value. The longer the Arch span and the deeper the depth, thebigger the stress superposition and the smaller the vertical stress superposition in farther archcorner. The arch axis of arch spanning strata deflected to the bottom, paralleling with tendencyof roadway.We designed the518B1supporting proposal, chose the optimized anchor bolt, cable andnet, defined the related supporting parameters, effectively controlled the deformation ofsurrounding rock and got praisable results, which could be referencable to collieries withsimilar condition.