Effects of Pore Fluid Compressibility on Liquefaction Resistance of Partially Saturated Sand

It has been recognized that the soil resistance to liquefaction increases significantly as the degree of saturation decreases. However, the effect of the degree of saturation reported in the literature varies widely between researchers. In this study, influential factors of the liquefaction resistance of partially saturated sand are derived from theoretical consideration and effects of the factors are examined through a series of triaxial tests. It was confirmed that the degree of saturation has a significant effect on the liquefaction resistance. It also appeared that the liquefaction resistance depends on the initial confining pressure and the initial pore pressure; the higher the confining pressure and the lower the initial pore pressure, the higher the liquefaction resistance of partially saturated sand. A unique relationship between liquefaction resistance ratios and the potential volumetric strain was found, which enable to estimate the liquefaction resistance of partially saturated sand with the effects of the three factors taken into account.