Support Technology of Reserved Rigid Gap Flexible Layer in High Horizontal Stress Soft Rock Roadway

In order to solve the engineering problem of large deformation and strong rheological behavior of a coal mine transportation roadway, the causes of large deformation instability and failure of roadway are summarized by the analysis of the ground stress test, the loose range of surrounding rock, the deformation and failure characteristics and the mechanical state of rock stratum. Based on the support theory of quantitative pressure, this paper proposes a joint support scheme of multi-stage anchor cable + reserved rigid gap flexible layer +U beam strong support. The optimal reserved space of rigid gap flexible layer was determined by FLAC^3D simulation. The industrial test shows that the maximum subsidence, floor heave and two sides moving amount of roadway roof are respectively 37.8 mm, 97.8 mm and 105.3 mm; the bolt axial force are in the range of 80 kN to 112 kN at roof and 78 kN to 137 kN at two sides after adopting the supporting technology, which effectively solves the engineering problem of large creep deformation of the transportation lane.