Effect of a shallow subway tunnel and adjacent foundation on the seismic response of ground surface
摘要
In dense urban environments, the vicinity of buildings with subway tunnels is unavoidable. In this study, a series of large shaking table tests and numerical analyses, using the finite difference method, were performed to investigate the effects of a shallow foundation and tunnel presence on the ground acceleration responses. Results indicated that a shallow underground tunnel and its features played a dominant role in the ground amplification pattern. In addition, a change in the frequency content of the input motion changed the peak ground acceleration (PGA) at different distances relative to the tunnel center line. On the other hand, the presence of a shallow foundation on top of the tunnel also slightly influenced the ground acceleration response of the model. It is shown that the foundation’s maximum impact on the ground acceleration is about 10% at a distance of 4 to 6 times the tunnel radius, relative to the tunnel center. Furthermore, tunnels with a lower flexibility ratio decreased the peak ground acceleration and consequently caused lower damage to the ground structure. In summary, the effects of tunnels and foundations on the PGA pattern should be considered in the design of buildings near subway tunnels.