摘   要

隧道 在臺灣鐵公路運輸及水利工程中均扮演重要之一環，近年來新規劃之隧道工程多位在高山峻嶺，如推動興建中之台9線蘇花公路改善計畫隧道群，各種困難地質與高岩覆問題使工程難度大幅提昇，隧道施工安全面臨嚴峻之挑戰。對於隧道施工可能遭遇之安全問題與評估方法，國內外雖已有許多研究成果可供參考，惟各研究成果零散於不同文獻或報告，在實際應用上仍需具豐富經驗之專業工程師方可彙整應用。鑑於國內隧道實際施工現場，仍有許多未經完整專業培養或僅熟悉部分業務之從業人員，對於隧道施工可能遭遇之各種安全問題與評估方法欠缺全面瞭解，以致問題浮現時，常錯失最佳因應時機，致使隧道施工出現不安全狀況仍時有所聞。

本研究之重點不在對於特殊困難或複雜問題做深入探討，而著重於實用層面，經由工程案例及相關文獻資料蒐集，將臺灣山岳鑽炸隧道施工常遭遇之安全問題，歸納分為強度應力問題、構造弱面安定、空間布置影響、洞口邊坡穩定、特殊地盤問題等五大類型。並進一步蒐集其安全評估方法，摒除理論深奧、過程複雜及參數繁多之方法，僅取其簡單實用者，透過評估流程之研提與VB.NET程式之撰寫，開發隧道施工安全評估系統，經實際工程案例評估應用，顯示系統具實用性，可適用於工地現場。本研究可將隧道研發成果推廣落實應用於工地，並提昇臺灣隧道施工水準。

Investigation of Safety Assessment Method in Tunnel Construction

ABSTRACT

Tunnel plays an important role in highway system, railway transportation, and hydraulic engineering in Taiwan. Recently, new tunneling projects are usually located in high-altitude mountain range. For example, eight tunnels in the improvement project of Suhua highway of Provincial Highway#9 are being constructed in precipitous mountains near Pacific Ocean. The safety of tunnel construction is very challenging due to difficult geology and high overburden depth. Many goals for tunneling safety assessments have been achieved around the world. However, these achievements are often published in different reports or in different time, which leads to considerable difficulty in performing tunneling safety assessment for an inexperienced engineer. Actually, there are many young tunnel engineers who need to work in the field before they can be trained professionally in Taiwan. In such scenario, these poorly trained engineers may not be able to deal properly with the complicated problems during the tunnel construction. Such delay in problem-solving results in tunneling instability which often happens in Taiwan.

Special difficulties and complicated problems in tunneling were not particularly investigated in the study. The basic assessments of tunneling problems were emphasized in the study to purpose the investigations fulfilled in practice. Based on the collections of case histories and publications for tunneling, this study divided the construction problems often encountered in Taiwan into five main groups, which are: (1) overstressed failure, (2) structurally controlled instability, (3) agjacent excavation influence, (4) tunnel portal hazard, and (5) special ground problem. The evaluation processes were conceived to assess the construction safety by simple calculating and illustrating with the matching chart. Accordingly, the safety assessment system for tunnel construction was developed by using the VB.NET program to provide the inexperienced engineer could reasonably estimate the tunnel safety when they encounter different difficulties in the field. Furthermore, the actual tunneling cases were adopted to demonstrate the appropriateness of the safety assessment system for tunnel construction. The application of the safety assessment system may reduce the tunneling risk efficiently and further upgrade the construction technique in the tunneling engineering in Taiwan.