Seismic response of a cut‐and‐cover tunnel isolated by polymer material |
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Authors: | Satoshi Kiryu Yoshitaka Murono Hitoshi Morikawa |
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Affiliation: | 1. Structure Engineering Division, JR East Consultants Company, , Tokyo, Japan;2. Earthquake and Structural Engineering, Railway Technical Research Institute, , Tokyo, Japan;3. Department of Built Environment, Tokyo Institute of Technology, , Tokyo, Japan |
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Abstract: | An effective method for the seismic retrofitting of the sidewalls of cut‐and‐cover tunnels has not yet been established. Thus, a new method of seismic retrofitting for cut‐and‐cover tunnels, called the ‘polymer isolation method’, is developed here. In this method, thin walls made of polymer materials, called ‘isolation walls’, are inserted between the ground and the sidewalls of a tunnel. We demonstrate the effectiveness of the proposed method in reducing the seismic response of tunnels by using some numerical simulations. It is found that the proposed method depends on the thickness of the soil cover over the tunnel and the ratio of the stiffness between the soil and the structure. Furthermore, a simple chart is proposed for convenience to represent the applicability of the polymer isolation method to the design of seismic retrofits for cut‐and‐cover tunnels. Although this particular chart has been obtained through a limited case, some other typical cases in which the chart can also be implemented for special conditions are addressed, and the applicability and the limitations of this chart are suggested for possible conditions of the ground and of tunnel structures. Copyright © 2012 John Wiley & Sons, Ltd. |
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Keywords: | cut‐and‐cover tunnels isolation wall polymer material |
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