Analysis And Study On The Stability Of Gob-side Entry Retaining Tunnel Surrounding Rock In Medium-thickness Seam

The fracture position of main roof in the tilt direction of working face is the key to success of the roadway retained. The stability of the B block provides theory basis for understanding the deformation features of roadway surrounding rock and carrying on roadside packing.Based on the previous research results, the surrounding rock deformation regularity of gob-side entry retaining with roadside packing under mining influence has been systematically analyzed with the key strata theory and the voussoir beam theory of the strata control, the stability coefficients K₁,K₂ have been put forward to reflect the stability characteristics of B block and four types of mechanical model indicating their basic characteristics have been designed, those are embed model, external embedded model, endo model, and the circumscribe model. Using numerical simulation, similar material simulation and field measurement, the general regulation of strata behaviors for different mechanics models have been analyzed comprehensively. The results indicate that the roadway retained has been influenced greatly with different fracture position of B block; the surrounding rock deformation of the endo model is the largest and that of the circumscribe model is the least, when the filling strength is low; however, when the filling strength is high, the yield zone changes little while the surrounding rock deformation of the embed model is the largest, that of the endo model is the least and the range of stress field in the roadway upper side is wide. Meanwhile, the fracture position of main roof at the 12101 working face end in Dongda coal mine has been analyzed, the types of stope structure has been expounded, the corresponding relation between B block structure and backfill structure has been established, and the layout scheme of roadside packing roadway retained of the 12101 working face has been put forward.The research results of this thesis have been verified in the roadway layout of the 12101 working face in Dongda coal mine and field application achieves good economic benefits.