Study On Stability Of Secondary Mining Surrounding Rock In Gob Side Entry Retaining Wall Of 12303 Working Face In Yun Jialing Coal Mine

Based on Yunjialing coal mine 12303 face tailgate as the research background,through the integrated use of theoretical analysis,numerical simulation,similar material simulation test and field industrial test,it shows the state of roadway surrounding rock stress distribution and evolution law of surface deformation law of surrounding rock of roadway and caving characteristics of the overburden influenced by secondary mining in Yunjialing coal mine.The optimal supporting scheme is put forward to investigate the regularity of surrounding rock in different phase.Through the numerical simulation technology to establish macro stope is apart from the working face is analyzed with the different distance,roadway influenced by secondary mining when the vertical stress of surrounding rock,the law of vertical displacement and plastic failure to distinguish and scope,through the analysis of known position in working face and return air lane cross perpendicular to the vertical stress is the largest,the roadway deformation is the most serious areas within the scope of the 20 m from working face,mining working face after mainly shear failure,damage depth in goaf under the 20 m.Thus targeted measures to reduce roadway influenced by secondary mining.Establish physical and mechanical model,through the simulation experiment,the migration law of overlying rock is simulated when the surrounding rock is affected by the secondary mining,through three bit static deformation measurement system we knew that the roof of the roadway is mainly parallel to the main settlement roadway affected by the secondary mining,and the influence on the deformation of the surrounding rock is greater than that of the first miningFinally,the effect of roadway support is monitored and evaluated by industrial experiments to provide technical support for the efficient roadway,providing theoretical support and experience reference for the overall design,parameter optimization and field implementation.The results show that the secondary mining breaking degree of the roadway is 50 percent of first mining.In order to make the lane more successful,we should pay attention to the pre tightening force of anchor cable in front of the working face 40 m,the anchor bolt and anchor cable are preload second times,so that the anchoring effect is the best.