Model optimization for seismic analysis of tunnels based on response displacement method

A beam-spring model, which takes account of tension, shear, and bending behavior of tunnel joints, is proposed in this paper. The model fully considers the characteristics of seismic responses for shield tunnels. Seismic analyses are carried out in longitudinal and transverse directions of a certain shield tunnel in the city of Shanghai through the response displacement methods. The analytical results show that, if compared with the traditional computational model, the optimized beam-spring model may give not only inner force responses of the lining, but also seismic response indexes of segment stress, joint deformation, bending capacity. Therefore the usability and safety of the tunnel during the earthquake and after the earthquake may fully be estimated. It may provide references to the seismic design and evaluation for tunnel safety.