Research on Stress Evolution Law and Support Optimization of Surrounding Rock in Retaining Roadway Along Goaf

Aiming at the large deformation problems of the surrounding rock such as coal wall caving, roof subsidence and others of the 11207 return air crossheading in Yuandatan Coal Mine caused by the goaf lateral support pressure and the instability of the overlying rock layer's arc-shaped triangular block structure of the nearby 11205 working face, based on the numerical simulation analysis of the evolution law of the roadway stress field, a collaborative support scheme is proposed: a load-bearing structure is formed by adopting high-strength threaded steel anchor rod + steel reinforcement and steel strip + short anchor cable on the deep part of the coal pillar side, while the fragmentation is controlled by conducting high-strength glass steel anchor rod and plastic steel mesh on the shallow part of the solid coal side. The industrial testing shows that implementing this collaborative support scheme significantly reduces deformation and failure of the roof and two sides, stabilizes the axial force of the anchor rod in a relatively quick speed, decreases the stable value of axial force, and effectively activates the self-bearing capacity of deep surrounding rock in the coal pillar.