Mechanical Mechanism of Surrounding Rock Failure and Stability Control for Gob‐Side Entry Driving Near an Advancing Working Face

ABSTRACT Addressing the challenges of surrounding rock control in gob‐side entry driving near an advancing working face affected by adjacent working faces and gobs, taking 5104 return airway of No.1 well in Checun Coal Mine as the background, using theoretical analysis, numerical simulation, and field measurement methods, the reasonable size of coal pillar for roadway protection is judged, the spatial stage evolution law of surrounding rock plastic zone in recovery mining roadway excavation is obtained, the mechanical mechanism of distribution characteristics change of surrounding rock plastic zone in recovery mining roadway excavation is revealed and the method of graded reinforcement and support for roadway surrounding rock is put forward and applied. The results showed that: (1) By establishing the mechanical model of gob‐side entry‐pillar surrounding rock structure and comparing the distribution characteristics of plastic zone in roadway excavation with different coal pillar widths, it is judged that the reasonable size of coal pillar is 12 m. The top angle of coal wall and the bottom angle of coal pillar are the key control parts of surrounding rock stability in roadway driving engineering. (2) The plastic zone of surrounding rock in roadway excavation shows five stages in axial direction, and the whole shows that the smaller the width of coal pillar, the larger the peak value of deviator stress in surrounding rock of roadway, the larger the gap, and the angle of maximum principal stress gradually deflects from horizontal to vertical direction, which leads to the increase of plastic zone range and the change of shape from symmetry to asymmetry. (3) The method of reinforcing support by stages is put forward, and the industrial verification of the proposed scheme is carried out. The deformation of surrounding rock of roadway tends to be stable and the control effect of surrounding rock is good.