Numerical investigation of the mechanical behavior of deformed segmental tunnel linings, strengthened by epoxy-bonded filament wound profiles

Large deformations of shield tunnels may be the consequence of a long period of operation or of nearby pit construction. To reduce them, a novel strengthening method was recently proposed. It makes use of epoxy-bonded filament wound profiles (FWP). Full-scale tests were performed to prove the effectiveness of this method. The present paper contains a report on a comprehensive parametric study of the influence of several design parameters, such as, for example, the mechanical properties of the bond between the FWP and a segment of the tunnel and Young's modulus of the FWP, on the increase of the load-carrying capacity of the structure. Several tests were conducted to obtain these parameters. The influence of the lateral earth pressure coefficient of the surrounding soil and of the geometry of segmental tunnel linings on the strengthening benefits was also investigated. The parametric study was based on a numerical model, established in the course of this research. It was validated by comparing the numerical results with the experimental results and by demonstrating the model's capacity to describe the experimentally observed failure mechanism of the strengthened structure. Based on this analysis, an optimum combination of design parameters for the proposed strengthening method is suggested to ensure its safety, reliability, and effectiveness.