a)Case2 (without shock absorption layer) b)Case3 (shock absorption layer)

Figure.5 Failure modes of tunnel model

There are a lot of circumferential cracks at tunnel portal, where the numbers of cracks are more than others position, as well as most of longitudinal cracks or diagonal cracks can terminate when extending to the circumferential cracks. So that it is proposed that there should be set up more shock absorption seams in the vicinity of tunnel portal in order to be propitious to damping the earthquake energy.

Shaking table model test shows that the tunnel damage position concentrates on the tunnel portal, which damage state is the same with the tunnel engineering damage in “Sichuan 5.12 Wenchuan earthquake”. Zhe hu shan tunnel occurred several times landslide and structure destruction during the Wenchuan earthquake and its aftershocks, which bring greater traffic obstacles for the rescue and disaster relief under the common effects secondary disasters and damage of the tunnel structure itself at tunnel portal.

6 Conclusions

Here we may draw the following conclusions.

(1) According to the tunnel internal force changes and failure modes, the largest dynamic response of tunnel structure appears at the side-wall and the shear or fracturing damage appears at the invert, which damage state is basically the same with tunnel engineering damage in 5.12 Wen Chuan earthquake. So that this model test is reliable.

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