ABSTRACT
Undrained cyclic loading tests are generally used to evaluate liquefaction properties of sandy soil. However, it is difficult to simulate the actual field soil behaviour through the laboratory liquefaction assessment due to the effects of sample disturbance, including loss of the aging effect on the particulate soil structure. In this study, in order to compare the liquefaction behaviour of in-situ frozen and reconstituted samples, undrained cyclic triaxial tests were performed. The specimens were consolidated isotropically to 100 kPa and static and dynamic measurements were conducted to evaluate the small strain quasi-elastic stiffness, which would reflect the soil structure before liquefaction. Moreover, since even the in-situ frozen sample may be disturbed by volumetric change during the freeze and thaw processes, the volumetric strains of frozen specimens were measured during thawing at different confining pressures of 30 kPa and 98 kPa. It was found that: (1) the quasi-elastic stiffness by static and dynamic measurements of the in-situ frozen sample was larger than that of the reconstituted sample during isotropic consolidation; (2) larger positive volumetric strain was observed during the thaw process at larger confining pressure; and (3) these features may affect the liquefaction resistance of the specimen, which may be also related to the loss of the aging effect on the soil structure.
