Effects of specimen density and initial cyclic loading history on correlation between shear wave velocity and liquefaction resistance of Toyoura sand

Abstract

Some previous studies have shown a good correlation between the shear wave velocity, Vs, and the cyclic resistance ratio, CRR. Recently, however, a Vs-based liquefaction assessment method has become an alternative and supplementary method to the conventional NSPT-based method. It is known that the CRR is influenced not only by the specimen density, but also by the soil fabric. Unfortunately, there are concerns that different combinations of the effects of the specimen density and the soil fabric may generate different relations between Vs and the CRR even if the tested specimens are of the same soil material. In the current study, a series of Vs measurements and undrained cyclic triaxial tests is performed on Toyoura sand specimens with different soil fabrics for three different specimen densities. The fabric of the specimens is varied by applying initial cyclic loading. The results of the Vs measurements indicate that the Vs of the specimen is affected by the initial cyclic loading histories, and the results of the undrained cyclic triaxial tests show that there is a good correlation between Vs and the CRR. However, the correlation varies depending on the specimen density even when the tested material is Toyoura sand only. In other words, the soil-type specific correlation between Vs and the CRR depends on the specimen density. Therefore, the results indicate that both Vs and the specimen density are necessary parameters for an accurate assessment of the CRR.