Evaluating liquefaction resistance of saturated sandy soils based on equivalent skeleton void ratio

In order to investigate the effect of physical properties on liquefaction resistance CRR, different types of saturated sandy soils (Fujian, Nanjing and Nantong sandy soils with different fines contents (FC)) are categorized as three different cases: (1) a fixed relative density D_r; (2) a fixed void ratio e; (3) a fixed skeleton void ratio e_sk. A series of isotropically consolidated undrained cyclic triaxial tests are performed on the three saturated sandy soils with various physical properties. The test results show that an increase in FC causes a decrease in CRR of saturated sandy soils at a constant D_r or e, and the CRR at a constant e_sk will increase with the increase of FC. Based on the test data here and from ten classified saturated sandy soils in the literatures, it is found that the CRR decreases monotonically with the increase of the equivalent skeleton void ratio $e_{\text{sk}}^{*}$, and a power relationship between CRR and $e_{\text{sk}}^{*}$ is then obtained, which means $e_{\text{sk}}^{*}$, synthesizing the nature of grain-size distribution, density state and intergrain contact, is an appropriate index of physical properties for evaluating the CRR of sandy soils. Moreover, it is first discovered that the best-fit parameters A and B of CRR-$e_{\text{sk}}^{*}$ correlation can be determined uniquely in terms of index properties of sand grains and fine grains for sandy soils. Consequentely, the CRR value of sandy soils can be captured only using index properties.