Evaluation of one-dimensional seismic site response due to liquefiable sub-layer

Although seismic site response is affected by liquefiable soil, the issue is complex and there are few comprehensive studies in this area. It is rare for seismic codes to consider attenuation or amplification of seismic waves due to the presence of liquefied sub-layers. In the research reported in this paper, the seismic behaviour of liquefiable sub-layers and their effect on seismic ground response were evaluated. The initial patterns of seismic response along the height of a soil profile containing a liquefiable sub-layer were extracted using physical modelling and shaking table tests. Afterwards, a series of one-dimensional effective stress numerical models was employed to verify the results and the seismic amplification patterns were processed. The roles of liquefiable sub-layers are discussed from different perspectives as they relate to attenuation or amplification of the seismic ground response at the surface. Overall, the experimental and numerical studies showed that the liquefaction of sub-layers, in addition to the usual settlement, can effectively attenuate the intensity of seismic waves and reduce earthquake-induced force.