Evaluating the effect of non-plastic fine content on the liquefaction potential of sandy soils

Abstract

This paper investigates the influence of non-plastic fine content (FC)on the liquefaction resistance of sandy soils through a series of cyclic direct simple shear (CDSS) tests. The study examines the development of excess pore water pressure (EPP) and the number of loading cycles required for liquefaction in sand-fine mixtures
with varying fine content (0% to 40%). The results show that EPP tends to increase with the number of loading cycles for all samples, but the rate of increase varies depending on the fine content. Notably, the sample with 20% fine content exhibits the highest EPP during mid-cycles, indicating significant interaction between sand and fine particles at this level. Regarding liquefaction resistance, the clean sand sample (FC = 0%) demonstrates the highest resistance, requiring the most loading cycles to reach liquefaction. However, as the fine content increases to 20%, the number of cycles needed for liquefaction decreases sharply, suggesting that
even a small amount of fine content can significantly reduce liquefaction resistance. Interestingly, when the fine content exceeds 30%, the liquefaction resistance improves again, highlighting the complex relationship between fine content and soil behavior. These findings suggest that fine content plays a critical role in influencing the liquefaction potential of sandy soils.

Keywords: Liquefaction resistance; fine content; cyclic direct simple shear test; excess pore pressure; number of cycles.