ISNL:建立新的量化土壤非線性效應參數;ISNL:A new parameter of soil nonlinearity

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Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/83417

Title:	ISNL:建立新的量化土壤非線性效應參數;ISNL:A new parameter of soil nonlinearity
Authors:	高靖;Kao, Ching
Contributors:	地球科學學系
Keywords:	土壤非線性效應;單站頻譜比法;土壤非線性度;DNL;ISNL
Date:	2020-07-28
Issue Date:	2020-09-02 15:37:07 (UTC+8)
Publisher:	國立中央大學
Abstract:	本研究嘗試擷取前人建立的幾種非線性度評估方式之優點，建立ISNL(Index of Soil Nonlinearity)參數，嘗試以低頻區域之放大行為作為顯著頻率降低之依據，而高頻區域之頻譜降低則可反映頻譜之壓抑放大現象，除了計算傳統 DNL 之區域差異外，並將測試評估此新建之非線性度評估方式之效益。本研究共使用6筆地震事件作為驗證ISNL之適用性，比較DNL及ISNL與PGV及PGV/Vs30後可發現2010 Darfield地震、2011 Christchurch地震及2018花蓮地震兩種非線性度皆呈現良好之正相關性，而2010甲仙地震、2016 Kaikoura地震與2016美濃地震ISNL則相對DNL呈現較好之正相關性，從上述結果我們可得出ISNL可以做為一良好之土壤非線性參數。本研究於紐西蘭區域之研究中可見ISNL之計算需額外考量區域間之差異評估，由於各區域間之地質地體構造之差異性，將造成參考之弱震平均頻譜反應之形狀將不同且附近之測站整體差異較小，由美濃地震與甲仙地震、Darfield地震及Christchurch地震兩組趨勢對照可見其互相之間之趨勢皆相近，代表未來若需應用至不同區域時皆須深入探討此區域之非線性強度、ISNL之建議門檻值等。 ;This study attempts to capture the advantages of several commonly used non-linearity evaluation methods,and try to establish an new index to identify soil nonlinearity (ISNL, Index of Soil Nonlinearity). The proposed method attempt to use the amplification behavior of the low frequency region as the basis for significant frequency reduction and the frequency spectrum reduction of the high frequency region can reflect the suppression of the spectrum. In addition to calculating the regional differences of traditional identification method (DNL, Degree of Nonlinearity), the benefits of this new non-linearity assessment method has been tested and evaluated. In this study, a total of 6 seismic events were used to verify the applicability of ISNL. Comparing DNL and ISNL with seismic intensity and strain level from strain proxy (use PGV and PGV/Vs30 as an index), it was found that the 2010 Darfield earthquake, the 2011 Christchurch earthquake and the 2018 Hualien earthquake showed good positive correlations in both methods. However, ISNL have better proportional correlation than DNL from the 2010 Jiaxian Earthquake, the 2016 Kaikoura Earthquake, and the 2016 Minong Earthquake. From these results, we can conclude that ISNL can be used as a good soil nonlinear identifier. Meanwhile, results in New Zealand showed the need for additional consideration of the regional differences assessment, due to the difference between geological ground structures between regions, result in different shapes of the reference spectral shape of weak motions. Finally, nonlinear intensity should be considered first in future applications in different regions due to two groups of trend discovered by the Meinong earthquake against Jiaxian earthquake and from Darfield earthquake and Christchurch earthquake, respectively.
Appears in Collections:	[Graduate Institute of Geophysics] Electronic Thesis & Dissertation

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