Seismic Performance of a Large-Diameter Shield Tunnel Crossing a Liquefaction River Valley Site by Different Anti-Seismic Mitigation Measures

A full-scale model of a 4.8-km shield tunnel was developed using authors’ dynamic sub-structure approach to evaluate and optimize anti-seismic measures. Lateral spreading is shown to aggravate longitudinal seismic damage causing excessive residual openings segment crushing degradation. For grouted structures residual opening is decreased when grout modulus is lower than rock and increased when stiffer. Inter-ring stiffness is raised by increasing longitudinal bolts changing from hinged-chain to quasi-continuous and inducing X-shaped segment damage. Residual opening is best limited by high-strength bolts SMA reduces crushing but poorly controls opening thus should be combined with high-strength bolts and higher concrete strength.