Heaving Floor Mechanism and Control Technology in Return Air Roadway of Fully Mechanized Mining Face

In order to solve the heaving floor problem in the return air roadway during the mining process of the I040901 working face in Qipanjing Coal Mine, methods of theoretical analysis, numerical simulation, and on-site testing are comprehensively adopted to study the forming causes and prevention and control technology of heaving floor in the return air roadway. The research results show that the key cause of heaving floor is that there has an incompletely collapsed roof in the goaf, which forms a cantilevered structure that causes stress redistribution in the roadway surrounding rock, resulting in relatively large horizontal stress on the floor, and exceeding the failure threshold. On this basis, a deanchoring and pressure relief governance scheme for the return air roadway in the goaf is proposed, and comparison and verification are conducted through ABAQUS finite element model and on-site monitoring data (error<8.5%). The on-site testing shows that after the deanchoring and pressure relief on the roof of the return air roadway in the goaf, the pressure is effectively released when the roof collapses in a timely manner. The amount of heaving floor before deanchoring is 1.19 m, and it drops to 0.246 m after deanchoring, with a reduction of 79.33%, the deformation of the heaving floor is effectively controlled. The research methods and proposed prevention and control measures can provide relevant guidance for the control problem of heaving floor in similar return air roadways.