2D seismic numerical analysis of segmental tunnel lining behaviour

Abstract

Segmental tunnel linings are now often used for seismic areas in many countries. Some prescriptions and guidelines specifically address the issue of seismic design. Unfortunately, the behaviour of segmental tunnel lining under seismic loads is still somewhat unclear. The influence of segment joints on tunnel lining behaviour during seismic loading has in fact not been quantitatively estimated in the literature. This paper presents a numerical study in order to investigate the performance of segmental tunnel lining under seismic excitation. Analyses have been carried out using a two-dimensional finite difference element model. The seismic signal obtained from an earthquake in Nice has been adopted as input. The numerical results show that a segmental lining can perform better than a continuous lining during an earthquake. The effect of plasticity of the soil constitutive model on the tunnel lining has also been highlighted. The results have indicated that an elastic analysis is not sufficient to determine the seismic induced response of a soil-tunnel system. Moreover, comparative results have pointed out that equivalent static solutions could result in smaller structural lining forces than those of a true dynamic analysis.