Study on Mine Pressure Behavior Law of Mining Roadway Passing Concentrated Coal Pillar and Goaf

Based on the special spatial position of 1-2 coal and 2-2 coal, this paper adopts a new way of modeling by fish and overcomes the difficulty of modeling, simulates the influence of the coal pillar on the 22,206 return airway after mining 1-2 coal seam by Flac3D, studies the 22,206 return airway under the influence of primary and secondary mining, and puts forward the support scheme of the 22,206 return airway. The following conclusions are obtained: (1) After mining 1-2 coal, the stress of the 22,206-return airway under the residual coal pillar of 1-2 coal increased. The maximum stress position is below the middle coal pillar of 1-2 coal, and its maximum vertical stress (sigma v(max)) and maximum horizontal stress (sigma h(max)) are 6.24 MPa and 4.09 MPa, respectively. (2) The rule of 22,206 return airway's pressure appearance is that the stress and plastic zone becomes larger when near the coal pillar, becomes smaller when far from the coal pillar, the maximum failure radius of roof and floor is only 1.3 m, and 0.6 m, the maximum failure radius of roadway side is 0.6 m and 1.5 m after the second mining. (3) According to the proposed support scheme, field experiments found that the maximum displacement is less than 120 mm, which can effectively guarantee the stability of the roadway.