Consolidating dredge soil by combining vacuum and dynamic compaction effort

Abstract

Increasing lands are being reclaimed at coastal areas by dredging soils from sea or rivers. Such formed lands are often characterized as presenting high water content, high void ratio, high compression, worst disturbance and weak bearing capacity, and thus cannot be directly used as a bearing deposit. It is time consuming to consolidate such lands by relying on naturally occurring evaporation and hydraulic dissipation. Enhanced engineered technology has to be introduced to expedite the dredge consolidation process. A technology, known as high vacuum densification method (HVDM), was developed to treat the dredge soil in a time-efficient and cost-effective means. Its principle is to consolidate the soil by combining vacuum effort and dynamic compaction. The vacuum effort is used to pump the moisture out of the soils in steps; and the drained soils are densified by dynamic compactions. Soils amenable to HVDM can be treated to favorable conditions meeting both strength and deformation requirements. Besides the principles and the construction procedures of HVDM, cases studies were also presented in this paper, which demonstrates the attractive merits of HVDM in contrast to comparable soil treatment methods.