Numerical study of seismic resistance of prefabricated circular tunnel linings

Abstract

Prefabricated circular tunnel linings are used in the construction of tunnels using the shield method, which significantly increases the speed and reduces the cost of building highways. Many methods have been developed for designing seismic resistant tunnel linings. Due to simplicity, analytical methods are usually used for preliminary design. In this case, the presence of joints between the blocks of the ring and between the rings is not taken into account. Compared to analytical methods, numerical methods, especially three-dimensional (3D), allow the most explicit consideration of the problem being solved. However, due to their complexity and time-consuming nature, 3D numerical models are only rarely used. In most reinforced concrete prefabricated linings, the deformation at the joints has a significant effect on the deformation of the rings. Thus, the magnitude and distribution of internal forces largely depend on the distribution and characteristics of the joints. Therefore, one of the most important factors in the design of a circular tunnel lining is the effect of segment connections on its overall behavior. This paper compares the internal forces that occur in the tunnel lining, determined using analytical analysis and numerical simulation in a three-dimensional formulation. When using numerical analysis methods, seismic loads are considered as quasi-static. However, almost all quasi-static analyzes presented in the literature include the same assumptions as closed form solutions and therefore have the same limited applicability. The main disadvantage of quasi-static models is that they do not take into account changes in the behavior of the structure over time.