Field Evaluation on the Strength Increase of Marine Clay under Staged Construction of Embankment

摘要

This article presents a case history of an embankment constructed on the soft Ariake clay on the bank of Rokkaku River, Saga, Japan. The staged method was used in the construction of embankment. To shorten the time of construction, the soft subsoil was treated by a prefabricated vertical drain (PVD). The physical and mechanical properties of soft subsoil, such as water content, unit weight, and unconfined com-pressive strength, were investigated before and during embankment construction. Based on the field data, the strength increase of Ariake clay during construction was revealed. A nonlinear relationship between strength increment and the degree of consolidation was found. Finite element method (FEM) was employed to investigate the strength increase behavior. The results showed that it is difficult to predict the filed behavior of strength increase using Cam-clay model. Based on the concept of structure loss of structured clay, the strength variation of Ariake clay during consolidation is discussed.