Consolidation mechanism of high-water-content slurry during vacuum preloading with prefabricated vertical drains

• Published in: Canadian geotechnical journal Vol. 59; no. 8; pp. 1373 - 1385
• Main Authors: Sun, Hong-lei, He, Zi-li, Pan, Kun, Lu, Jing-ling, Pan, Xiao-dong, Shi, Li, Geng, Xue-yu
• Format: Journal Article
• Language: English
• Published: 1840 Woodward Drive, Suite 1, Ottawa, ON K2C 0P7 Canadian Science Publishing 01-08-2022; NRC Research Press; Canadian Science Publishing NRC Research Press
• Subjects: Analysis; boue de dragage; Clay; Clay soils; colonne de sol; Composition; Compression; Compression zone; Consolidation; Deformation; Deformations (Mechanics); Drainage; Drains; dredged slurry; déformation; Environmental aspects; Moisture content; Particle image velocimetry; PIV; Prefabrication; préchargement sous vide; Reclamation of land; Slurries; Slurry; Soil; soil column; Soil columns; Soil mechanics; Soils; Vacuum; vacuum preloading; Vertical drains; vélocimétrie par image de particules; Water; China
• ISSN: 0008-3674; 1208-6010
• DOI: 10.1139/cgj-2021-0248

Vacuum preloading combined with prefabricated vertical drains (PVDs) has been widely used to improve soft clayey soil deposits. However, the consolidation deformation of high-water-content slurry under vacuum pressure is still not fully understood. In this study, the displacement field of the slurry during vacuum preloading was directly observed using the particle image velocimetry (PIV) technique. The test results showed that the displacement field of the slurry could be divided into three different zones that reflect distinct consolidation patterns. In zones I and III, the slurry was predominantly compressed along the horizontal and vertical directions, respectively, whereas in zone II, compression occurred in both vertical and horizontal directions. In particular, the slurry elements in zones I and II underwent horizontal extension prior to horizontal compression. The study also visualized the boundary of the soil column and provided an equation for the relation between soil column thickness and consolidation time, which could provide a reference for the theoretical consolidation calculations related to soil columns.