地下單與雙隧道受地震作用之動力反應

Dynamic Response of Underground Single and Twin Tunnels to Earthquakes

林偲妘(Szu-Yun Lin)

指導教授 ： 楊永斌

國立臺灣大學/工學院/土木工程學研究所/碩士(2015年)

https://doi.org/10.6342/NTU.2015.11063

摘要

由於都市人口增加，土地資源受限，在人口密集的大都會，許多重要的基礎設施皆須建築於地下，除了污水、自來水、電力、電信等管線，還包括鐵路、捷運等公共運輸系統，地下化的優點不外乎節省地面空間、減少噪音及降低天候的影響。然而，當破壞性地震發生時，這些地下結構物往往首當其衝，若造成破壞或坍塌，則很可能造成大眾生命財產的損失。為能對隧道受震問題有所理解，吾人希望藉由數值分析方法，模擬地下隧道受地震力作用之行為，以供未來工程師設計之參考。
本研究採用Yang et al. (1996)提出之有限與無限元素混和分析法，模擬二維土壤－結構互制系統，並參考Zhao and Valliappan (1993)提出之地震力入方式處理波散射問題，建立一合理的地震輸入機制，以模擬自由場所紀錄的實際地震之作用。在數值分析中，吾人將採用921集集地震的實測資料，以模擬地下單孔隧道與水平雙孔隧道在地震力作用下之反應，接著，進一步探討隧道深度、間距、襯墊及土層剪力波速對地表和隧道的影響，最後，將利用多層土壤模型，討論不同土層組成下隧道之受震反應。
由研究結果發現，在地震力作用下，隧道襯墊、土壤勁度與不同土層組成，會顯著影響隧道及近域土壤之動力反應；然而，隧道所處深度與兩隧道間距雖會影響隧道之主應力分布，但對於受震時之地表反應影響較不明顯。

關鍵字

二維有限元素與無限元素混和分析法 ； 土壤－結構互制 ； 半無限域 ； 隧道 ； 雙孔隧道 ； 互制行為 ； 受震反應

並列摘要

In densely populated metropolitans, it is beneficial and desirable to construct the transportation system and other networks of lifelines underground, such as subways, water, gas, and electricity pipes. During a devastating earthquake, such vital infrastructure may be damaged and become dysfunctional, resulting in the loss and damage of lives and property. As part of the effort to address the above issue, the purpose of this thesis is to study the seismic responses of underground tunnels, including twin-tunnels, and the effect of tunnels on the seismic responses of the ground and tunnels.
In this thesis, the finite/infinite element approach proposed by Yang et al. (1996) is adopted to simulate the two-dimensional response of an elastic half space containing cylindrical tunnels subjected to vertically incident body waves. In addition, to deal with the scattering of seismic waves, the procedure of simulating earthquake excitations proposed by Zhao and Valliappan (1993) is adopted. Then a reasonable procedure will be presented for imposing the excitations based on the free-field motions recorded for earthquakes. Particularly, the free-field seismic motion recorded for the 921 Chi-Chi Earthquake will be adopted in the seismic responses of the underground tunnels. Furthermore, a parametric study is performed to investigate the effects of tunnel depth, spacing between the twin-tunnels, stiffness of the tunnel lining, and Young’s modulus of the soil on the ground and tunnel responses. In the end, the effect of different soil compositions of the half-space is discussed.
The results from this study indicate that the seismic responses of the tunnels and the ground will be affected significantly by the tunnel lining, stiffness of the soil, and different soil compositions of ground. Even though the tunnel depth and spacing between the twin-tunnels are important parameters with respect to the seismic responses of the tunnels, they have less effect on the ground responses.

並列關鍵字

2D finite/infinite element method ； soil-structure interaction ； half-space ； tunnel ； twin-tunnels ； interaction behaviors ； seismic response

參考文獻

林冠中 (2013)，隧道結構在地震波傳下之反應，國立台灣大學土木工程研究所碩士論文。

高任璋 (2009)，地下捷運引致之地表振動，國立台灣大學土木工程研究所碩士論文。

鄭凱文 (2012)，隧道受地震和移動列車載重之動力反應，國立台灣大學土木工程研究所碩士論文。

游佩琳 (2014)，地下雙孔隧道受震反應分析，國立台灣大學土木工程研究所碩士論文

Achenbach, J. D. (1973). Wave Propagation in Elastic Solids. The Netherlands: North-Holland Publication Co.