天然氣網絡震災韌性分析—以臺南市新化區為例

Abstract

現今社會中，地震災害不僅損害建築物，對於重大基礎建設的衝擊如自來水、汙水、電力、瓦斯與其他維生管線等也大大影響災後的民生生活水準，本研究欲針對維生管線中的天然氣管線，分析中低壓管線受到地震災害破壞之風險，並考慮搶修管線時開關閥關閉將擴大影響範圍。地震災害除了造成天然氣網絡系統本身的影響外，洩漏的氣體還造成了震後火災惡化的潛在風險；另一方面，受損管線的修復可能會影響地震災害時的緊急避難交通，這些相依性因素都應在修復過程中加以考慮。本研究藉由臺灣地震損失評估系統(TELES)預估地震參數與天然氣網絡系統之GIS圖資進行疊圖分析。採用管線災損率(Repair Rate, R.R.)之方式評估管線耐震能力，以蒙地卡羅模擬(Monte Carlo Simulation)天然氣管線破壞，並透過受影響用戶需求端數量來衡量整體網絡之供氣能力。本研究以臺南市新化區與中洲構造斷層規模6.9想定地震為分析案例，參考國內外文獻提出的管線震災模擬分析方法，考量災害當下應變時開關閥關閉擴大影響範圍之情況、評估惡化震後火災的風險以及緊急避難交通之影響，提出綜合的天然氣網絡震災韌性分析框架，決策者可以根據模擬結果作出適當的應對策略。

Earthquake disasters not only deal damage to buildings, but also may significantly affect people’s lives owing to the impacts on critical infrastructures such as water supply, wastewater, electricity, gas, and other lifeline systems. This study will focus on the natural gas network, analyzing the risk of failure in the mid/low-pressure pipelines from the earthquake scenario. During the assessment, it is also considered that the closure of valves as the emergency response could enlarge the affected range. In this study, repair rate, R.R. is applied to evaluate the failure of natural gas pipelines. The simulation of the natural gas network is conducted with Monte Carlo method. In addition to the impacts within the natural gas system itself, the leaking gas may also cause a potential risk of worsening post-earthquake fire. On the other hand, the repair of damaged pipelines may affect the traffic. These cascading effects should be considered during the restoration process. This study refers to the domestic and foreign literature on the method proposed for the simulation analysis of pipeline subject to earthquake disasters, considering the closure of valves, the risk of worsening post-earthquake fire and the influence on traffic. This study provides an analytical framework to access the earthquake hazard risk of natural gas pipelines from the perspective of system functionality and community resilience. The proposed method is demonstrated on the natural gas system in Xinhua District, Tainan, subject to a 6.9 magnitude earthquake scenario. Decision makers can refer to the simulation results when planning related emergency responses and disaster mitigation strategies.