Coupling Bearing Analysis And Control Of Backfill Body And Surrounding Rock In Gob-side Entry Retaining

Based on the geological conditions of the gob-side entry retaining in the 3414 working face of Xinyuan Coal Mine,The interaction principle and coupling relationship between backfill body and surrounding rock are theoretically analyzed.Combined with numerical simulation and orthogonal test,the influence of backfill body,immediate roof,immediate floor,solid coal elastic modulus and size on the coupled bearing capacity of gob-side entry retaining is discussed.Then the coupling bearing control technology of backfill body and surrounding rock stability is put forward.The main research results are as follows:(1)Based on the analysis of the interaction between the backfill body and surrounding rock,the coupling bearing system on both sides of gob-side entry retaining is put forward.Constructing coupled load-bearing mechanical models of backfills and surrounding rocks,and obtaining coupling coefficient function and influencing factors of coupled bearing coefficient.The theory shows that the smaller the coupling coefficient,the poorer and more unstable the matching between the backfill body and the surrounding rock;otherwise,the better matching the more stable and stronger bearing performance of the backfill body and the surrounding rock.(2)The influence of the surrounding rock mechanical characteristics and size on the deformation and bearing capacity of surrounding rock in gob-side entry retaining by numerical simulation and orthogonal test.The elastic modulus of the backfill,direct top,direct bottom,solid coal,the width of the backfill,and the thickness of the direct top are increased,the coupled bearing factor is increased,which improves the coupled carrying capacity of the backfill and surrounding rock.The degree of damage to the direct filling area roof and the floor,the width of the roadway,mining height and the depth of coal are increased,the coupling bearing coefficient shows a decreasing trend,which is not conducive to the stable carrying of the retained roadway,and provides basis for optimizing surrounding rock coupling bearing control technology.(3)Multi-region enhanced coupled-bearing control technology that strengthening roadway support,controlling roof separation and preventing floor floor heave is proposed.Reinforcement for backfill body,solid coal,filling area roof and floor will improve the stability and coupling bearing effect of surrounding rock.Combining with the geological conditions of Xinyuan Coal Mine,the deformation,stress,and coupling load laws of surrounding rock under different reinforcement support techniques are analyzed to invert the coupled control process.The coupling bearing effect of the gob side entry retaining is evaluated under the coupling control technology,and the coupled bearing control technology that satisfies the normal use of gob-side entry retaining was determined.(4)According to the coupled bearing mechanism and control technology of the surrounding rock in gob-side entry retaining,the mine pressure observation plan for the gob-side entry retaining of Xinyuan Coal Mine was determined.Comparative analysis of the coupling bearing rule of the surrounding rock mass in the gob side entry retaining with unconsolidated support and reinforcement support is carried out.The reinforcement of solid coal can improve the stability of the surrounding rock,which is conducive to the coupled bearing of surrounding rock in gob-side entry retaining.In other words,under the coupled control scheme,the surface displacement,deformation speed,and the amount of separation of surrounding rock can be effectively reduced,and the coupling control effect of surrounding rock is better.