最大熵與證據理論在液化潛能分級之應用

Application of the Maximum Entropy and Evidence Theories on Ranking Evaluation of Soil Liquefaction Potential

紀雲曜(Y. Y. Chi) ； 李上妤(S. Y. Lee) ； 李雅芬(Y. F. Lee)

《中國土木水利工程學刊》 20卷1期 (2008/03) Pp. 1-16

https://doi.org/10.6652/JoCICHE.200803_20(1).0001

摘要

建築基地若具有高液化潛能之土層，則評估其受地震作用時之可能損害程度，為目前都市及防災規劃重要課題之一，但因可應用的液化損害評估及分級的方式相當多，以致進行液化潛能分析時，常面臨評估結果分歧的不確定問題，導致決策困難。本文乃基於常用之現地試驗資料、液化簡易法與Iwasaki 液化潛能指數之分級法，應用最大熵與證據理論，發展一客觀的液化潛能綜合分級評估方法；首先以最大熵理論客觀地率定各種資訊量的優先度，再以證據理論及其運算規則進行綜合評估，以獲得液化潛能分級決策輔助資訊，包括分級、決策支持度與決策不確定性，最後，本文並以921地震發生液化之員林崙雅里地區點位為案例，說明方法程序與液化潛能圖繪製，可供都市液化防災規劃之參考。

關鍵字

液化 ； 潛能評估 ； 證據 ； 不確定性

並列摘要

The risk analysis of liquefied soil foundation of structure by earthquake is one of important topics of urban hazard prevention. There are a variety of liquefaction potential evaluation methods and various models in classifying the degree of liquefaction potential, which makes it vague for liquefaction potential ranking decision. This study applies the maximum entropy and evidence theories to develop a new integrated ranking evaluation model of liquefaction potential based on field data, simplified methods and ranking evaluation methods of Iwasaki’s liquefaction potential index. Firstly, the individual criterion priority values of decision alternatives of liquefaction potential ranking are evaluated by the maximum entropy theory. By applying the combination rules of the evidence theory, this study integrated rationally different evaluation results by the simplified method and the classification method in the degree of liquefaction potential index. Finally, the liquefied and non-liquefied cases during the 921 earthquake in central Taiwan in 1999 are examined by the proposed method. Our results show that through the proposed method, we can choose the suitable classification and also obtain its degree of uncertainty, which can provide better suggestions in the decision making for urban hazard mitigation during earthquake.

並列關鍵字

liquefaction ； potential evaluation ； evidence ； uncertainty