| dc.description.abstract | 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. | en_US |