Mechanism and application of concrete-filled steel tubular support in deep and high stress roadway

Abstract The concrete-filled steel tubular (CFST) support has been proposed as a new passive support form for controlling the stability of surrounding rock in deep roadway. To explore the mechanism of CFST support in deep roadway, the mechanical performances of U-steel support and CFST support were compared by theoretical calculation and numerical simulation with the engineering background of 11031 ventilation roadway in Pingmei coal mine. Then, the section shape of CFST was optimized and the special-shaped CFST support was put forward. The special-shaped CFST support was applied to 11031 ventilation roadway of U36-steel support failed to control. The results indicate that: The ultimate bearing capacity of CFST support is much greater than that of U-steel support. The CFST support can provide great supporting force to the roof-floor and two sides of roadway. It can be applied to the roadway with large horizontal stress. The section bending modulus and ultimate bearing capacity of the special-shaped CFST support are greater than those of the circular CFST support. The displacements of 11031 ventilation roadway supported by the special-shaped CFST support was not great. So, the special-shaped CFST support can effectively control the surrounding rock in 11303 ventilation roadway.