英文篇名
APPRASIAL OF SPT-N METHODS IN LIQUEFACTION ANALYSIS BY USING THE CHI-CHI EARTHQUAKE DATA CASES
作者
黃俊鴻、楊志文
關鍵字
液化、簡易法、成功率、安全係數、誤差指標、適用性、集集地震
摘要
以現有SPT-N簡易法評估土壤之液化潛能,結果常有顯著之差異。瞭解各方法之適用性,就變成工程界待解決之重要課題。本文以評估方法之判定成功率與至少安全係數誤差指標Fm為評估指標,利用302筆集集地震液化與非液化案例資料評估國內常使用五種液化評估方法的適用性。判定成功率代表一個方法判定液化與否之準確程度,Fm代表誤判時之相對安全係數誤差程度。評估結果顯示以NCEER’97法與Seed’85法之整體判定成功率最高,至少安全係數誤差指標Fm最小,可認為適用性較佳;T-Y’83法及JRA’96法之表現次之,適用性也次之;JRA’90法表現最差,可認為是較不適用之方法。
英文摘要
Great discrepancies are often found between the evaluated results, when using various simplified SPT-N methods to evaluate soil liquefaction potential. Therefore, it is important to know which simplified method is more suitable for use. However, this problem is not solved yet. Using a total of 302 liquefied and non-liquefied cases during Chi-Chi earthquake, this paper proposed two assessment indices, prediction success rate and at-least safety factor error, to appraise the suitabilities of the five simplified SPT-N methods currently used in Taiwan. Success rate is an index that represents the accuracy of a method in predicting whether liquefaction occurs or not. On the other hand, at-least safety factor error is an index to indicate the relative error of the calculated safety factor by a method. Based on the appraisal, it is found that among the five methods, the success rates of NCEER’97 and Seed’85 methods are the highest and their at-least safety factor error are also the lowest, thus, these two methods can be considered to be most suitable methods. The performances of T-Y’83 and JRA’96 methods are the second. The JRA’90 method has the worst grade, therefore, it is believed to be an unsuitable method.