A Computational Method for Ground Penetrating Shield Tunnel

For the super-shallow embedded tunnel - like a ground-penetrating shield tunnel (GPST) - the internal force and deformation of the lining are quite different from the normal ones. This paper adopts the nonlinear shell spring model to simulate the behavior of a lining. Taking the configuration of lining joints into consideration, a 3D numerical model was taken to calculate the stiffness of longitudinal joints and the lining behavior is further analyzed. The results show that in super-shallow embedded tunnel, the moment is larger while the axial force is smaller compared with the general one. Also, the bending stiffness of the longitudinal seam joints becomes smaller and behaves non-linearly. What's more, the shell spring model is compared with the mean ring method. The contrast analysis shows that, for conventional tunnels, the internal force calculated by a nonlinear shell spring model is close to the results by the mean ring model; but, the deformation values are significantly different. Therefore, it is necessary to consider the non-linear joints stiffness in the calculation of the super-shallow embedded tunnel.