A Large Strain Consolidation Model for Dredged Clays with High Water Content under Vacuum Preloading

摘要

Newly dredged clay is commonly hydraulic mud that contains a large amount of fine soil particles and has a higher water content. The dredged clay is often times too soft for the surcharge to be applied. Vacuum preloading technology can be an attractive technology rather than surcharge preloading. In order to better apply vacuum preloading technology to dredged clays, it is necessary to establish a large strain consolidation model. Based on the Gibson's one dimensional large-strain theory and Barron's free strain theory, and abandoning the equal strain assumption, introducing the negative pore water pressure boundary condition, a large strain consolidation model is established by incorporating the radial and vertical flows and the weight of the soil. The material nonlinearity is considered in the large strain consolidation model. It is found that the nonlinear compression and nonlinear permeability have the significant influence on the consolidation effect. In addition, the large strain vacuum consolidation model is compared with the small strain degradation consolidation model, the two models differ greatly in excess pore pressure dissipation and degree of consolidation. The large strain vacuum consolidation model must be taken into account in the prediction of vacuum preloading effect of dredged clays.