Liquefaction resistance of sand-silt mixtures: an experimental investigation of the effect of fines

The liquefaction resistance of a saturated fine to medium sand mixed with varying amounts of non-plastic fines was evaluated by laboratory cyclic triaxial tests. The test results were used to draw conclusions on the effect of fines content on the liquefaction potential of the mixtures in relation to the global void ratio as well as to the intergranular and the interfine void ratios. It was found that for fines content increasing from 0 to 44% the liquefaction resistance of mixtures with constant global void ratio decreases compared to that of the clean sand, whereas this trend is reversed for values of fines content greater than 44%. However, when intergranular or interfine void ratios were kept constant, the liquefaction resistance of the mixtures varied monotonically (i.e. continuously increased or decreased, respectively), for increasing values of fines content. The test results were also (a) examined in terms of the conceptual framework of Thevanayagam [20] whose predictive power was validated and (b) compared to seemingly contradictive results from the literature, which were reconciled when the variation of intergranular void ratio of the soil was taken into consideration.