Performance-based analysis of tunnels under seismic events with nonlinear features of soil mass and lining

Abstract

Accurate prediction of tunnel behavior and damage states under seismic loading remains a challenge. This study carried out tunnel behavior and risk assessment using numerical dynamic analysis on a NATM tunnel. A hypoplastic model that considers intergranular strain was calibrated for a particular sand using experimental tests and numerical simulations. It then was used in numerical simulations for the surrounding soil to allow precise prediction of soil dynamic behavior at all ranges of strain. The elastic perfectly plastic model was used for the tunnel lining to detect plastic hinges under seismic motion. Similar trends for all drift-PGA curves at different surcharges and soil densities indicate that all models experienced the same phenomena at similar time intervals and represent different performance levels. The serviceability level of the tunnel is the point at which the first plastic hinge forms. The collapse prevention level produces failure mechanisms that cause instability and collapse.