Liquefaction analysis of Izumio sands under variation of ground motions during strong earthquake in Osaka,Japan

This paper presents a study of liquefaction analysis at sand layers of the Izumio site, under ground motion variation during a strong earthquake in Osaka, Japan. Site investigation using standard penetration test and shear wave velocity measurement is conducted. Finite element liquefaction site response analysis integrated with a strain space multiple mechanism model is conducted. Ground motions variation is considered based on the seismic record at surrounding seismic stations. Attenuation analysis is conducted to determine the scaling factor for ground motions. Several results, such as acceleration profiles and cyclic behaviours are presented. The empirical analysis is also conducted to verify the results of the numerical analysis. The results explained that cyclic behaviours of sandy layers in the Izumio site show the liquefaction tendency. The results also showed that sandy layers are indicated as critical layers during the strong earthquake due to the excess pore water pressure reaching the liquefaction threshold. The results of the empirical analysis also present liquefaction indication at sand layers under the variation of ground motion, since the factor of safety against liquefaction is less than 1. The results are generally well-agree with liquefaction evidence and prediction presented in the previous study. The results could bring practical importance in understanding liquefaction potential in the study area.