Fabric characteristics and processes influencing the liquefaction and re-liquefaction of sand.

Abstract

Although the density of sand has long been considered to be the predominant factor for liquefaction resistance, observations during earthquake sequences and laboratory tests have suggested that other factors may also cause significant anomalies in the relationship between density and liquefaction resistance. This study pinpoints the fabric characteristics and processes influencing the liquefaction resistance of sand. Numerical DEM tests on 2D polydispersed circular granular material are conducted on specimens with various stress-strain and liquefaction histories, showing that changes in micromechanical fabric characteristics of sand can indeed influence its liquefaction resistance, even overpowering the influence of overall density under certain conditions. The liquefaction resistance of initially isotropic sand is strongly correlated with the amount of increase in mean neighboring particle distance needed for it to reach liquefaction (ΔMNPDliq). Smaller ΔMNPDliq results in weaker liquefaction resistance. Fabric anisotropy also significantly affects the liquefaction resistance of sand, due to its influence on dilatancy. Greater fabric anisotropy intensity results in smaller liquefaction resistance. The findings in this study enhances the understanding of liquefaction behavior of sand by establishing a link between the changes in quantifiable fabric states and liquefaction resistance.