Coupled Effects of Spatially Non-Uniform Ground Motions and Bolt Corrosion on Seismic Response of Long Large-Diameter Shield Tunnels

As critical infrastructures, long, large-diameter shield tunnels require a reliable long-term seismic safety assessment. This study investigates the coupled effects of spatially non-uniform ground motions and bolt corrosion on the seismic response of long, large-diameter shield tunnels. Three types of non-uniform seismic waves (coherent, traveling, and coherent traveling) consistent with the design spectrum were generated, and a 3D discontinuous finite element model was used to analyze tunnel response under various corrosion locations and rates. Results show that non-uniform excitation significantly amplifies the seismic response in the order coherent traveling waves > traveling waves > coherent waves > uniform waves, with coherent traveling waves amplifying key seismic responses by up to 10 times compared with uniform excitation. Corrosion at circumferential joints causes more substantial responses than at longitudinal joints, and combined longitudinal corrosion shows a greater effect than single-joint corrosion. Under coherent traveling waves with high corrosion rates, the seismic response exhibits a distinct “top stronger than bottom” distribution. This study concludes that accurate seismic performance evaluation requires consideration of both variability in spatial ground motion and bolt corrosion, thereby supporting the seismic design and long-term maintenance of such structures.