Research on earthquake dynamic behavior of uneven multi-section subway tunnel in transverse direction

Model tests are carried out in this research to investigate the dynamic behavior of multi-section cut-and-cover subway tunnels in the transverse direction by seismic motion, which has not been fully investigated up to now. Multi-section model and general single-track box-section model tunnels are installed in a soil vessel, and it is found that the sectional force corresponds to that obtained in the tunnel design. Then, L2 earthquake motion (Spectrum II), based on the design standard for railway structures, is applied to the soil vessel. The test results show that the bending moment and shear force are comparatively large in the center wall, although the tendency is different in the loading direction. Moreover, the results of a 3D dynamic finite element analysis for an evaluation of the model tests show approximately the same situation. This research provides various findings for establishing a seismic analysis method for multi-section cut-and-cover subway tunnels.