Transitional behaviors in well-graded coarse granular soils

Drained triaxial compression tests were carried out for a well-graded coarse granular soil (CGS) to investigate the effect of the initial specific volume on the location of the critical state line (CSL). A family of parallel CSLs in the v ~ log p' plane was observed for the well-graded CGS, indicating that it exhibited transitional behavior. The degree of transitional behavior was quantified from the relationship between the intercepts of the CSLs and the initial specific volumes, giving a value of 0.59, which indicated a substantially transitional behavior. The observations of the CSL pattern in the CGS illustrated that transitional behavior could be extended to large-sized granular soils, beyond the usual transitional soils that have been observed so far, which generally have gradings between those of clean sand and plastic clay.