Abstract Using the Beijing Metro line 7 as an example, a numerical model of the closely overlapping tunnels was established by FLAC3D finite difference software and the seismic response characteristics of the tunnels during a strong earthquake were studied by inputting Beijing Hotels horizontal earthquake waves at the model base. The calculations indicate that in the closely overlapping tunnels, horizontal displacement of the uppertunnel is greater than that in the lower tunnel, and the maximum relative horizontal displacements at the tunnel crown of both the upper and lower layer were found to be at the middle overlapping part. Additionally, the maximum acceleration response of the non-overlapping part was found at both the upper tunnel floor and the lower tunnel crown. Compared to the shallow-buried tunnel, the horizontal displacement and stress of the upper layer has a magnifying effect to different degrees, and the peak acceleration is reduced; compared to the deep-buried tunnel, the horizontal displacement of the lower layer has a magnifying effect, while the accelerated speed and the stress is reduced to different degrees.
Abstract：
Using the Beijing Metro line 7 as an example, a numerical model of the closely overlapping tunnels was established by FLAC3D finite difference software and the seismic response characteristics of the tunnels during a strong earthquake were studied by inputting Beijing Hotels horizontal earthquake waves at the model base. The calculations indicate that in the closely overlapping tunnels, horizontal displacement of the uppertunnel is greater than that in the lower tunnel, and the maximum relative horizontal displacements at the tunnel crown of both the upper and lower layer were found to be at the middle overlapping part. Additionally, the maximum acceleration response of the non-overlapping part was found at both the upper tunnel floor and the lower tunnel crown. Compared to the shallow-buried tunnel, the horizontal displacement and stress of the upper layer has a magnifying effect to different degrees, and the peak acceleration is reduced; compared to the deep-buried tunnel, the horizontal displacement of the lower layer has a magnifying effect, while the accelerated speed and the stress is reduced to different degrees.
Keywords：
published: 2013-04-23
Cite this article:
LI Ji-Dong,
Tao-Lian-Jin,
Wu-Bing-Lin etc
.Analysis of 3D Dynamic Response of Closely Overlapping Tunnels During
a Strong Earthquake
[J] MODERN TUNNELLING TECHNOLOGY, 2014,V51(1): 26-31
2014, Vol. 51 