Search

Lime treatment combined with vacuum preloading has been used in the treatment of dredging slurry for many years. Previous studies have indicated that particle grading, which is one of the essential properties of slurry, could affect the pore-size distribution and compression characteristics of slurry and thus affect the efficacy of the lime treatment and vacuum preloading. However, the effect of particle grading has not yet been examined quantitatively. This study investigated the compressibility of lime-treated slurries with different particle gradings using a one-dimensional oedometer for compression testing. A series of laboratory model tests were carried out to examine the effect of particle grading on the efficacy of lime-treated slurry with vacuum preloading. The results showed that particle grading significantly influences optimal lime content. For clay or low-plasticity silt, the optimum lime content for lime treatment combined with vacuum preloading was found to be 2%. When slurry contains increased silt and sand grains, more lime is required to achieve effective lime treatment. However, excessive lime would reduce the efficacy of lime treatment on the compressibility and permeability of the soil. [ABSTRACT FROM AUTHOR]

Based on the vertical equal strain assumption, there are many consolidation theories of soft soil incorporating vertical drains. Because the influence of many factors is often ignored and the flow of the pore water usually happens in three-dimensional directions, analytical solutions could not be accurate enough. Because of the amount of computer storage and the computing time needed, two-dimensional finite element analysis is used to model the stone column improving the soft foundation. The embankment load is transferred to a column because of the soil arching effect. When the embankment is constructed, the settlement accounts for 64% of the total settlement, which shows that the column can reduce the post-construction settlement. The stone column's bulge is confined to a length about one to two times the diameter of the stone column away from its top, and the column at the toe would bears the shear stress to some extent. [ABSTRACT FROM PUBLISHER]