The effect of PVD layout on the consolidation characteristics of dredged slurry under vacuum preloading

Abstract

Vacuum preloading coupled with prefabricated vertical drains (PVDs) has been widely used to improve the property of the dredged slurry. However, the effect of PVD layout on slurry consolidation characteristics remains poorly understood. This study conducted two vacuum preloading model tests—with single and dual PVDs. Particle image velocimetry (PIV) was used to directly observe the slurry displacements and strain paths. The test results revealed that the slurry consolidation characteristics were similar under different PVD layouts in the early stage of vacuum preloading. However, in the mid-stage, the effect of dual PVDs led to a significant reduction and increased dispersion of the slurry horizontal displacement. This, in turn, resulted in a thinner clogging zone and a subsequent decrease in vacuum pressure loss. Consequently, the slurry near the PVDs experienced an extended period of consolidation deformation. During the later stage, the single PVD model test exhibited a distinct zone of both vertical and horizontal compression in the slurry, while under dual PVDs, the slurry primarily underwent vertical compression and horizontal extension. The study also provided the relationship between the clogging zone thickness and time, which provided a reference for theoretical consolidation calculations.

The Hydrolysis Characteristics and Compressibility of Soft Clay Soil Improved Using VCM

“…Cai [11] used 2 PVDs to look at the behavior of the soil within the clogging zone; the results stated the transmitted vacuum pressures of the two PVDs offset each other in the horizontal direction, resulting in a thinner clogging zone, thus improving the pore water pressure dissipation efficiency. The study proved that PVD, individually and together with others, gives slightly different results.…”

One-Dimensional Consolidation Properties of Soft Clay under Multi-Stage Loading

“…This complexity is a major factor contributing to errors in Terzaghi's classical consolidation theory [7]. For instance, in highway construction, preloading is often employed to mitigate post-construction settlement and reduce the construction period [8][9][10]. Accurately predicting embankment settlement is crucial for ensuring the stability of the foundation [11,12].…”