EXPERIMENTAL STUDY ON COLLAPSE MECHANISM OF TUNNEL LINING AND EFFECT OF REINFORCING MATERIAL ON LOAD-BEARING CAPACITY OF TUNNEL LINING

Full-scale tunnel model tests under a few kinds of load conditions have been performed to clarify the collapse mechanism of tunnel lining and the effect of reinforcing material on the load-bearing capacity of tunnel lining. It is found that tunnel lining reaches the state of entire structure collapse when the cross-sectional failure by compressive stress due to bending or development of tensile cracks at three locations on a tunnel cross section, or the shear failure by axial compressive stress at a location on a tunnel cross section occurs depending on the load conditions. Furthermore, it is verified that steel-fiber-reinforced concrete and reinforced concrete have the effect of improving the load-bearing capacity of cross section or entire tunnel lining structure depending on the collapse patterns.