Impact of joint interactions in concrete segmental tunnels: Advanced numerical modeling for seismic resilience

Ensuring the seismic resilience of segmental tunnels is essential for safeguarding urban transportation systems, especially in earthquake-prone areas where structural integrity is critical. Conventional seismic analysis methods typically rely on simplified models, utilizing homogeneous beam or shell elements with equivalent stiffness properties to approximate tunnel behavior under seismic loading. To overcome these limitations, this study presents an advanced, high-fidelity numerical model tailored for segmental tunnels, incorporating material and geometric nonlinearities while maintaining computational efficiency. The proposed model uses fiber beam elements to precisely represent the reinforced concrete segments. In contrast, zero-length section elements simulate the intricate interactions between tunnel joints, bolts, gaskets, and concrete surfaces. The model's accuracy is rigorously validated through experimental data from three distinct loading scenarios, confirming its capability to reliably predict the seismic response of segmental tunnels. Beyond experimental validation, a comprehensive sensitivity analysis is performed to examine the influence of different segment assembly configurations on the seismic behavior of tunnels. The findings indicate that the arrangement and mechanical properties of the segments significantly affect the overall structural performance, highlighting the necessity of precise modeling techniques. The proposed model is a valuable tool for enhancing the seismic design of underground transportation networks by offering a more detailed and accurate representation of segmental tunnel behavior.