台灣山岳隧道脆弱性曲線建立之初探

Abstract

由於台灣多山的地形環境且多地震，山岳隧道縮短通行時間，改善交通便利性。為了瞭解台灣山岳隧道受震反應以及後續的維護，故希望能初步探討台灣山岳隧道之脆弱性曲線。 本研究使用FLAC 2D數值軟體進行山岳隧道受震模擬之分析，採用嘉寶隧道周圍的岩石材料參數，並且除了加入不同的影響因子如覆土深度和隧道支撐類型之外，也加入回歸期設計地震進行分析。最後選取輸出結果作為隧道損傷指標，建立山岳隧道之脆弱性曲線。 結果顯示不同的覆土深度和隧道支撐類型影響著隧道的破壞機率，且回歸期設計地震的加入導致破壞機率上升，此研究結果初步說明影響因子對於台灣山岳隧道的破壞機率改變，期望能協助往後相關的研究發展。

Taiwan has a mountainous terrain. A lot of mountain tunnels were constructed to shorten the travel time between cities and accessibility of mountain area. However, Taiwan is seismically active, hence it is crucial to understand the seismic performance of these mountain tunnels, their maintenance needs, and the repair and recovery time if damages are induced during earthquakes. The objective of this study is to develop the seismic fragility curves for the mountain tunnels in Taiwan. This study uses FLAC 2D numerical software to simulate and analyze the seismic response of mountain tunnels. The Jiabao Tunnel in Taitung county was used as a baseline case. In addition to incorporating different influencing factors such as overburden depth and tunnel support types, input motions with different ground motion characteristics were used in the analyses. The relative displacement between the crown and the inverted arch , as well as the crown peak acceleration were selected as the tunnel damage indicators to establish the fragility curves for the mountain tunnels. The results indicate that different burial depths and tunnel support types can influence the probability of tunnel damage. This study preliminarily demonstrates how these factors alter the probability of damage of Taiwan's mountain tunnels subjected to seismic loading, aiming to assist future related research endeavors.