A method for detecting site liquefaction by seismic records

作者：Yuan Xiaoming^*; Sun Rui; Chen Longwei; Tang Fuhui

来源：Soil Dynamics and Earthquake Engineering, 2010, 30(4): 270-279.

DOI：10.1016/j.soildyn.2009.12.003

• Acceleration records
• Liquefaction detection
• Natural frequency decreasing ratio of site
• Time-frequency decreasing ratio of surface acceleration
• Two-degree-of- freedom model

A simple semi-theoretical method for straightforward identification of the liquefied site by using Surface acceleration records is presented by taking the natural frequency decreasing ratio of the site (NFDRS) as a fundamental benchmark and taking the time-frequency decreasing ratio of the surface acceleration (TFDRSA) as a basic index. The TFDRSA of an accelerogram is calculated and the critical point of the TFDRSA is taken as a divisive point which distinguishes liquefied sites from non-liquefied sites. The critical point Value of TFDRSA is assumed to be equal to the lower limit of NFDRS caused by liquefaction and the lower limit of NFDRS is attained approximately by a two-degree-of-freedom system which is employed to simulate site liquefaction. Based on the analysis for actual earthquake records, it is proved that the theoretical model and the basic assumption here are reasonable. The reliability of the method in the paper is verified by tire actual earthquake records and the comparison results indicate that the method can detect the liquefied site and non-liquefied sites including the soft sites correctly.

• 出版日期2010-4
• 单位中国地震局; 中国地震局工程力学研究所