Research on the bond‐slip behavior and constitutive relationship between I‐shaped steel and shotcrete in tunnel

Abstract

The failure of the initial support of the tunnel caused by the synergistic deformation of steel and shotcrete under high‐ground stress is expected to be solved by arranging studs and steel webs to enhance the structure's bearing capacity. Hence, the bond‐slip mechanism of steel shotcrete with or without studs is unclear. This study aims to determine the bond behavior of the interface between the steel and shotcrete composite structure for tunnel support. The findings of push‐out experiments demonstrate that shotcrete on steel flange longitudinal splitting failure is the failure mode of natural bonding specimens. Tensile failure and expansion failure under the effect of studs is the failure mechanisms of stud steel‐sprayed concrete specimens. Furthermore, experimental data and a mathematical model establish the bond‐slip constitutive law of natural bonding and stud specimens. Finally, in addition to providing a theoretical foundation for the research of bond‐slip, the constitutive model put forward in this paper also supports the prevention of initial support failure in tunnel engineering.