State-Dependent Volume Change during Creep in Engineered Silty Sand

Abstract

To investigate the volumetric creep behavior of engineered sand containing nonplastic silt, a series of creep tests was performed under various stress conditions and initial void ratios. It was found that contractive or dilative volumetric creep behavior was determined by a specific combination of the void ratio (ec) and the mean normal effective stress (pc′) at the beginning of creep. Based on the experimental results, the range for which no volumetric change occurs during creep was determined, and this group of specific combinations of ec and pc′ was defined as the zero-creep volume change zone (ZCVZ). The contractive or dilative volume change pattern during creep can be predicted by the positions of ec and pc′ relative to the ZCVZ on the e−logp′ plane. The creep mechanism of the observed volumetric behavior was explained by adopting the microscopic mechanisms of dislocation slip and the recovery process in the creep of metals.