STRAIN RATE EFFECT ON LONG-TERM CONSOLIDATION OF OSAKA BAY CLAY

The consolidation characteristics of clay, based on the isotache concept in which the strain rate effect is considered, have been studied by many researchers. Most of these studies are aimed at calculating the secondary consolidation with high accuracy in order to evaluate the long-term settlement of large structures. In this study, as the first step toward improving the accuracy of the evaluation of long-term settlement at the Kansai International Airport, the consolidation characteristics of Osaka Bay clay are examined and organized based on the isotache concept. This study proposes a simplified model based on the isotache concept by using a compression curve and the relationship between the consolidation yield stress and the strain rate. The former and the latter are obtained from the constant rate of strain consolidation (CRS) tests and long term consolidation (LT) tests, respectively. The latter is expressed by an equation with three isotache parameters. This model is very practical because it requires a minimum of only one CRS test and one LT test. It is widely applicable to the Osaka Bay clay. The isotache parameters used in this model can be commonly determined for the Osaka Bay clays retrieved from various depths at the Kansai International Airport.