Critical state and static liquefaction resistance of sand with low-plastic fines via equivalent void ratio concept under varied stress histories

Limited research has explored how fines content impacts static liquefaction at critical state in soils with different stress histories using the equivalent void ratio concept, especially when considering fabric techniques. This study bridges this gap through undrained triaxial tests analyzing the effects of fines content and stress history on critical state behavior in clean and silty sand specimens. Specimens were reconstituted with systematically varied fines content, packing densities, and fabric techniques. Results showed that for a given stress history and initial density, dry pluviated specimens displayed a consistent decline in critical state shear strength as fines content increased. In contrast, moist-tamped specimens exhibited an opposite trend, with increasing low-plastic fines significantly enhancing shear strength across all parameters. Stress history was found to increase critical shear strength in all cases. Furthermore, the equivalent granular void ratio concept unified steady-state/critical-state data into a single relationship in the e * –log ( p′) space, termed the equivalent steady-state line, particularly for dry pluviated specimens. These findings advance understanding of sand–fines mixture behavior, including flow potential and mechanisms influenced by stress history.