Parametric analysis of the seismic response of coupled tunnel-soil-aboveground building systems by numerical modelling

During an earthquake, the presence of tunnels may affect the seismic wave propagation in the involving soil and in turns the response of aboveground structures. At the same time, the vibrations of aboveground structures may create a complex interaction with the tunnel and, consequently, they may modify the dynamic response of the tunnel. Most of the published papers considered only tunnel soil systems or only soil aboveground structures; analyses involving tunnel plus soil plus aboveground structures (full coupled analyses) are still very rare. The present paper deals with a parametric analysis: starting from a real case-history regarding the Catania (Italy) underground network, and in particular a cross-section including an aboveground building, the depth of the tunnel, the position of the aboveground building and the seismic inputs were modified in order to study their effects on the dynamic tunnel soil aboveground building interaction. Thirty different recorded accelerograms were adopted. Results are reported in terms of accelerations in the time and frequency domains, as well as in terms of seismic bending moments and axial forces of the tunnel lining.