Study on Design Model of Quasi-Rectangular Shield Tunnel Linings

In order to obtain a design model for quasi-rectangular shield tunnel linings, a full-scale ring test was conducted to acquire the deformation and internal forces of the linings with loads simulated according to the actual ones in normal operation conditions. The test results were then analyzed in comparison with the numerical results based on the equivalent stiffness model and the beam-spring model, to determine parameters of the design model of quasi-rectangular tunnel linings. Results show that using the equivalent stiffness model to design of the quasi-rectangular shield tunnel linings, the segment stiffness reduction factor that can account for the deformation along both the long and short axes could not be obtained. While applying the beam-spring model, the computed structural responses and the influence of longitudinal joints on moment distribution both agree well with the experimental results. Therefore, it is more reasonable to use the beam-spring model as the design model of quasi-rectangular shield tunnel linings. For the quasi-rectangular shield tunnel linings under study, input parameters for the design model, including the shearing rigidity, negative-moment bending rigidity, and positive-moment bending rigidity of segment joints, are recommended as 341 × 10⁶ − 368 × 10⁶ N/m, 114 × 10⁶ − 491 × 10⁶ N•m/rad, and 85 × 10⁶ − 177 × 10⁶ N•m/rad, respectively