An updated spectral representation method coupled with generalized probability density evolution method in assessing the seismic reliability of tunnels

The dimension reduction spectral representation method (SRM) is generally employed with the generalized probability density evolution method (GPDEM) to implement the seismic reliability assessment, where a noticeable non-zero value in the mean value of ground motion would be obtained. This study proposed an updated spectral representation method (U-SRM) to improve the simulated mean values, which coupled with GPDEM to investigate the nonlinear responses and seismic reliability assessment of a tunnel. Results obtained from the numerical study were compared between SRM and U-SRM. The horizontal displacement at the tunnel crown is more conservative using U-SRM than SRM in the reliability assessment of tunnels. Results indicated that U-SRM coupled with GPDEM is an efficient method to analyze the nonlinear responses and the seismic reliability of tunnels, and could serve as a reference for tunnel design in seismically active zones.