Influence of plastic fines content on the liquefaction susceptibility of sands: cyclic loading

Abstract The paper presents an experimental study on the effect of plastic fines content on the undrained behavior and liquefaction susceptibility of sand-fines mixtures under cyclic loading. The results of undrained cyclic triaxial tests conducted on mixtures of Hostun sand with varying amounts (0–20%) and types (kaolin and calcigel bentonite) of plastic fines are presented. The specimens were prepared with different initial densities using the moist tamping method, consolidated at the same isotropic effective stress of 100 kPa and subjected to different deviatoric stress amplitudes. From the experimental observations, it was found that sand-clay mixtures with 10% or 20% clay content showed a lower cyclic liquefaction resistance than pure sand. Furthermore, the reduction in the cyclic stress ratio resulting in liquefaction after twenty cycles was found larger for sand-kaolin mixtures than for the sand-calcigel ones. Possible explanations are provided.