performance-based seismic assessment of shallow tunnels using pushover analysis

This paper aims to use pushover analysis for performance-based seismic assessment of linings of shallow tunnels constructed in soil that are subjected to vertical shear waves. pushover analysis is a nonlinear static analysis that works based on pushing laterally two-dimensional (2d) numerical nonlinear model of soil with tunnel statically. this analysis considers just ovaling/racking deformation of a lining and compared to the other existing seismic analysis approaches, it has the advantage of using directly a standard acceleration response spectrum as seismic demand. initially in this paper, responses of a typical tunnel due to four earthquakes were calculated using pushover analysis. then, the approach of employing a typical standard acceleration response spectrum as seismic demand was presented using the building standard spectrum of fema 302 provisions. all the resultant performance points of pushover analyses were then evaluated by carrying out nonlinear dynamic time history analyses and the method was verified. however, further studies are required to propose an acceptable response spectrum for the geotechnical nature of soil deposits containing shallow tunnels as their seismic demand.