Influence of anisotropy on liquefaction/reliquefaction resistance of granular materials and its quantitative evaluation

Abstract

In situ survey revealed that sand that experienced liquefaction history in the mainshock may liquefy again (called reliquefaction) when suffered an aftershock. Sometimes aftershocks might cause more severe damage to infrastructure. Previous studies revealed that the reliquefaction resistance was influenced by many factors, especially the anisotropic fabric. However, the influences of initial anisotropy and stress-induced anisotropy on reliquefaction response are still unclear, especially the mechanism of the stress-induced anisotropy and its quantitative evaluation. Therefore, two groups of cyclic triaxial tests were firstly carried out on sub-angular sand, reconstituted by different methods, to illustrate the influences of anisotropy on liquefaction and reliquefaction response. According to test findings, a new parameter, named definitive anisotropy degree, was proposed to quantitatively evaluate the anisotropy. Another group of cyclic triaxial tests were also performed on spherical glass beads with no preferred orientation, based on which an explanation of the mechanism of stress-induced anisotropy for different geomaterials was given at the end.