Abstract
It has been reported in many research papers that considerable settlements are observed in the Osaka Pleistocene clay layers, even though their stress levels are less than their yield consolidation pressure (pc). To study the consolidation behavior around the pc value, Long Term Consolidation (LTC) and Inter-Connected Oedometer (ICO) tests were carried out. This paper presents the consolidation behavior measured by the LTC, while the companion paper describes the results from ICO test. The LTC test is conducted using the conventional oedometer, whose diameter and initial height are 60 mm and 20 mm, respectively. The maximum duration for the consolidation was half a year. The tested clays are mainly Osaka Pleistocene clays. Test results from these clays are compared with those from Holocene clays retrieved from various sites across the world. Relationship between the strain and elapsed time measured by this study has been analyzed in terms of the strain rate theory. Based on test results from the Osaka Pleistocene clays, the family of equi-strain rate lines is proposed, consisting of three regions. However, in case of other clays, whose OCR is probably created by stress changes, i.e., mechanically overconsolidated clays, the consolidation behavior is different from that of the Osaka Pleistocene clays : i.e., a certain pressure exists where no more strain is yielded even after the strain rate becomes small.
