Experimental and numerical evaluation for tunnel structural stability of fiber concrete lining with different crack features under train load

Abstract

Cracks are prone to occur in the secondary tunnel lining with the action of train loads, which will cause tunnel failure and adversely affect the long-term safety of tunnels. This paper conducts a series of material tests and numerical simulations to investigate the stability of fiber concrete tunnel linings with different crack features under train load. Through material tests for three different fiber and conventional concrete, the crack extension rule is discovered by combing digital image correlation (DIC) technology. The plastic damage constitutive relation of concrete is used to obtain the damage parameters. Then, the three-dimension numerical model is established to evaluate the stress intensity factor and stable coefficient of safety of tunnel lining. Moreover, four cases are determined to indicate the effect of cracks on the failure mechanisms of the tunnel lining structure. The influence of stability of lining structure with crack at different location, depth, width, inclination angle, train speed and grade of surrounding rock is analyzed.