Influence of Nonlinearity in Shield Tunnels on Seismic Response

In recent years, with the increasing size of shield tunnels, the influence of foundation's shear deformation on transverse direction can no longer be neglected. Many earthquake-resistant codes in Japan have been revised by adopting two design levels representing low-to-moderate and strong earthquakes, especially after the Hyogo-ken Nanbu Earthquake. So far, the earthquake-resistant calculation to the transverse direction of shield tunnel is still employing elastic analysis that is obviously inappropriate to the high-level (strong) earthquakes. It is necessary to take the discontinuity of the shield tunnel and nonlinear characteristic of joints and segments into account in terms of high-level (strong) earthquake. Due to the above-mentioned reasons, this paper analyzes the following items on the shield tunnel applying the seismic deformation method based on finite element method, and rational earthquake resistant calculation method is put forward as well: (1) the influence of nonlinear characteristic of joints and segments; (2) the influence of longitudinal discontinuity; and (3) the application scope of the simplified method based on an elastic ground beam theory.