Numerical Investigation of the Seismic Performance of FRP-Reinforced Tunnel Linings Under Dynamic Excitation

Tunnel linings are critical structural components of underground infrastructure, and their seismic performance plays a decisive role in maintaining the serviceability and safety of tunnels. Under dynamic loading, excessive deformation and damage of the lining may reduce the effective cross-sectional capacity and threaten the minimum safety clearance required for tunnel operation. Therefore, it is essential to investigate the deformation behavior and failure mechanisms of tunnel linings subjected to seismic excitation and to evaluate the effectiveness of reinforcement measures. In this study, a coupled numerical framework combining the finite difference method (FLAC3D) and the discrete element method (PFC3D) is developed to analyze the dynamic response of tunnel lining systems. The surrounding rock mass is modeled in FLAC3D to simulate stress wave propagation and global deformation, while the tunnel lining is represented in PFC3D using bonded particles to capture crack initiation, propagation, and post-peak failure behavior. The proposed FLAC3D–PFC3D coupled approach provides an effective tool for evaluating the seismic performance of reinforced tunnel linings and offers a practical basis for the design and assessment of seismic strengthening measures in underground engineering.