Abstract
Standard consolidation tests were carried out to investigate the characteristics of the coefficient of secondary consolidation using pure clay minerals, a remolded clay soil, and undisturbed Ariake clays. The coefficient of secondary consolidation was almost constant for kaolinite, serisite and a halloysite soil over a given range of consolidation pressure, while the coefficient of secondary consolidation versus consolidation pressure relations showed upward convex curves for bentonite and Ariake clay. The secondary consolidation characteristics of remolded clay samples were different according to the type of clay mineral of the samples. With increasing the consolidation pressure, the coefficient of secondary consolidation increased up to a maximum at around a consolidation yield stress for the undisturbed Ariake clays and then decreased. The ratio of the coefficient of secondary consolidation to compression index was almost constant for the undisturbed Ariake clays, with 0.029 to 0.049 in a 95% confidence interval, at the consolidation pressures above the consolidation yield stress, which was within a range proposed by Ladd et al.
