Influence of novel polymer waterproofing membrane on mechanical properties of tunnel lining structure

Abstract

The composite shell lining of tunnels uses an adhesive waterproofing membrane to replace the traditional sheet waterproofing membrane, which can improve the waterproofing performance of the tunnel and provide excellent mechanical characteristics. To calculate and design the lining structure, it is necessary to evaluate the influence of the existence of the bond interface on the mechanical behaviour of the lining structures. In this study, a four-point bending test was performed on a reinforced concrete beam with a novel polymer waterproofing membrane and the degree of composite action was quantitatively calculated. Under the bonding effect of the waterproofing membrane, the beam with the waterproofing membrane had a certain degree of composite action, and its strength and stiffness were also significantly improved compared with the beam with a sheet waterproofing membrane. ABAQUS software was used to establish the numerical calculation model of the beam with a spray-applied waterproofing membrane verified by testing, and the influence of the interface on its mechanical behaviour was analysed. The degree of composite action also increases with an increase in the waterproofing membrane thickness and interface stiffness.