Influence of a layered liquefiable soil on seismic site response using physical modeling and numerical simulation

Abstract

In this research, the seismic behavior of liquefiable sub-layers and their effect on seismic ground response have been evaluated. The initial patterns of seismic response along the height of a layered liquefiable soil are extracted using a series of shaking table testing. The sub-layers of the shaking table models were built with different densities and the models were subjected to specific record motions of varying intensity. Afterwards, in order to use compatible constitutive model in numerical analysis, a series of effective stress numerical models have been employed while the results were verified adequately with the results of the shaking table test. Dafalias-Manzari model was utilized in the current study as a suitable constitutive model. The effect of depth and height of liquefiable sub-layers is discussed from different perspectives as it relates to attenuation or amplification of the seismic ground surface response. Consequently, experimental and numerical studies of this research have shown that contrary to the usual view, the thicker and shallower liquefiable sub-layers can effectively reduce the intensity of seismic waves and earthquake-induced forces. However, the thinner liquefiable sublayers at greater depths could increase seismic intensity and reduce settlement.