Effect of content and plasticity of fines on liquefaction behaviour of soils

The purpose of this study is to investigate the effect of content and plasticity of fines on the liquefaction resistance and the post-liquefaction volumetric strain (epsilon(v,pl)) of soils through a series of cyclic triaxial tests with remoulded samples considering various levels of cyclic stress ratio (CSR). Silt and clay were employed as the fines material, and the dry deposition method was used to prepare remoulded samples. Test results showed that for soils with silt fines (S soils), increase of fines content (FC) reduces the liquefaction resistance and causes larger epsilon(v,pl). Conversely, for soils with clay fines (C soils), increase of FC raises the liquefaction resistance and results in lower epsilon(v,pl). For the same level of FC and CSR, the liquefaction resistance of C soils is higher than that of S soils. The epsilon(v,pl) of S soils is greater than that of C soils. For S soils, the epsilon(v,pl) rises with increasing FC, whereas for C soils, the inverse result is obtained. These results show that the plasticity of fines affects the liquefaction behaviour of soils significantly.