Mechanical analysis of the stability of surrounding rock of goaf roadway in deep well

The roof and coal pillar of goaf roadway are the whole of coordinated deformation, and the stability of coal pillar is the key to the whole stability of surrounding rock of goaf roadway. In order to study the factors affecting the stability of surrounding rock of goaf roadway, the development law of the limit plastic zone of coal pillar under different influencing factors and the roof subsidence rule under the influence of secondary mining are analyzed by theoretical analysis, numerical simulation and field experiment based on the engineering background of 131306 working face of mining area. The results show that the buried depth and mining height of working face are positively correlated with the development range of limit plastic zone of corresponding coal pillar. With the increase of friction and friction angle and the decrease of Poisson’s ratio, the development range of limit plastic zone of coal pillar decreases. With the increase of support strength, the development range of limit plastic zone of coal pillar decreases. By comparing the impact range of primary and secondary mining through numerical simulation and combining theoretical analysis, it is concluded that the theoretical value of roof subsidence in 131306 working face of wind alley under the influence of secondary mining is 580 mm, which is greater than the in-situ measured roof separation value of 468 mm. Combined with in-situ drilling and observation, it is proved that the roof displacement can be effectively reduced by reasonable setting of coal pillar width. The stability of surrounding rock of goaf roadway is effectively controlled. The research results provide theoretical support for the research of the stability of the surrounding rock of the goaf roadway in deep well and have the engineering guiding value.