地震災害引發避難救災路網阻斷風險之研究──以臺中市高脆弱度社經環境地區為例

Risk assessment of road failures after earthquakes - An example of high socio-economic vulnerability region in Taichung City

由於都市路網在地震災害發生後會面臨極大的破壞性，所以有必要探討災後可能影響避難救災路網有效性之各項實質因素，因此本研究以臺中市高脆弱度社經環境地區為例分析震後建物倒塌所引致避難救災路網阻斷之風險問題。在此本研究發展出一個建物脆弱度評估法為概念之評估程序，進而規劃該地區最小震災風險的避難救災路網，研究整體架構為：1.藉由TELES模式進行強地動資料之模擬；2.高脆弱度社經環境地區之分析：3.建物基本資料庫建置；4.藉由TELES模式進行建物倒塌機率的推求；5.路網阻斷風險機率值的推求以及6.避難場所可及性評估。本研究分析了地震災害引致避難救災路網阻斷風險與緊急疏散路線規劃之相關問題，而研究成果表明臺中市當中的「中區」與「南區」係為地震災害中避難據點與路網脆弱度最高之兩個地區，這兩區於震災過後似乎有可能存在無法提供災民可靠路網至避難據點之問題，未來上述區域應透過災害管理規劃手法降低地震災害所發生之衝擊性。而本文最大的研究貢獻則是針對都市高風險環境地區，可就都市防災觀點，提出系統性避難據點可及性之評估策略。

The road systems in the metropolitan areas may be damaged during an earthquake, causing difficulties to disaster response and rescues. This study performed a risk analysis of an earthquake scenario to evaluate the vulnerability of road systems and the impacts of traffic failure. A case study of Taichung city was included to discuss the failure risk of emergency evacuation. Data for Taichung city buildings and road networks were analyzed. A hybrid-assessment procedure of road failure risk analysis had been developed based on the TELES model and the building vulnerability assessment. The proposed analysis procedure includes simulation of a strong motion using the TELES model; analysis of areas of high vulnerability to the socioeconomic environment after an earthquake; construction of a database of building attributes; estimation of the probability of building collapse by TELES model; assessment of road failure risk; evaluation of emergency evacuation routes based on the safety and the risk of a road failure. The procedure was applied to 5 districts of Taichung city. The analysis results indicated that the Central District and the South District of Taichung city were highly vulnerable to the road failure. Therefore, residents from these areas may have difficulty evacuating to shelters after a strong earthquake. The disaster management and evacuation plans of these areas should be reconsidered to reduce the risk of a road failure. The proposed risk analysis procedure improves risk assessment of road failure, especially in the metropolitan areas.