Professor, Chung Yuan Christian University, Chung-li, Taiwan
(Received 9 August 2000; accepted 29 May 2001)
Natural soft clays are frequently encountered in civil engineering projects. Such soils possess large compression potential that needs to be alleviated by means of effective ground improvement techniques. Current knowledge on mixing soft clay with small cement content to improve its consolidation properties is limited. This study looks into the consolidation behavior of undisturbed lacustrine soft clay treated with small cement contents. Based on the pH values of soft clay and cement mixtures, small cement contents of 3 and 6% were chosen to prepare soft clay-cement oedometer specimens. The oedometer test results show that the preconsolidation pressure may be decreased or increased, depending on the cement content added. The secondary compression index is reduced and the ratio of secondary compression index to compression index is also reduced, indicating a change in grain size characteristics. The coefficient of consolidation is reduced for consolidation pressures near the effective overburden pressure and is about equal or slightly increased for consolidation pressures higher than the preconsolidation pressure. These data indicate that treating natural soft clay with cement at small cement contents can be effective in reducing both primary and secondary settlements.
Paper ID: GTJ11079J