Evaluation of Marine Clays’ Strain Rate Dependency During the Unloading Process

Consolidation characteristics interpreted with the isotache concept have been studied by many researchers. However, the dependency of strain rate on the unloading behavior of marine clays remains unclear. In this study, the authors conducted Constant Rate of Strain (CRS) consolidation test and Incremental Loading Oedometer Test and evaluated a ratio (Ccα/Cc and Csα/Cs) to compare the strain rate dependency between loading and unloading. The ratio Csα/Cs exhibited an increasing trend with overconsolidation ratio ( \(OCR = p_{\max }^{\prime } /p^{\prime }\) ). Moreover, the Incremental Loading Oedometer Test revealed an approximately linear relationship between the unloading strain rate (in log scale) and the elapsed time (in log scale). These findings contribute to a better understanding of the behavior of marine clays during consolidation and unloading processes.