Numerical Investigation on the Mechanical Characteristics of a Special-Shaped Shield Lining with a Large Cross-Section

A shell-spring finite element model of a special-shaped tunnel was established to investigate the distribution of internal forces and deformation mode of the lining at the designed buried depth. The numerical results were compared with prototype loading test results and uniform beam model, which showed that the shell-spring model can be an optimal model to calibrate the 3D distribution of the internal forces and deformations of the special-shaped tunnel. Finally, the internal forces in the design condition were given. Furthermore, the economy and mechanical property of a special-shaped tunnel were compared with circular and rectangular tunnels with the same dimension and joint parameters. Results showed that the proposed special-shaped tunnel was more suitable for shallow overburden ground.