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Ultrasoft Ground Treatment of Vacuum Preloading Combined with Calcium-Based Flocculants

Auteur(s):






Médium: article de revue
Langue(s): anglais
Publié dans: Advances in Civil Engineering, , v. 2020
Page(s): 1-12
DOI: 10.1155/2020/6691565
Abstrait:

Vacuum preloading is one of the popular methods improving the engineering properties of slurry ground with high water content. Commonly, the efficiency of vacuum preloading gradually decreased due to the clogging of prefabricated vertical drains (PVDs) and the low-vacuum transmission rate inside slurry. Thus, the calcium-based flocculants were used to accelerate the dewater capacity and enhance the soil strength during vacuum preloading. This paper performed a series of model tests to investigate the effect of calcium-based flocculants on the efficiency of vacuum preloading. It is found that the vacuum transmission rate was significantly improved by flocculants in comparison with raw slurry. Accordingly, the after-treatment undrained shear strength increased with the vacuum pressure, while the after-treatment water showed a decrease trend. This suggests that the increase of vacuum transmission rate inside the slurry due to the calcium-based flocculants was the main reason for the improvement of efficiency of vacuum preloading. In addition, there existed an optimal flocculants amount, where the vacuum pressure increased with flocculants’ amount up to this threshold value, followed by a decrease in vacuum pressure. This means that, at lower flocculants amount, the increase in soil flocs due to flocculation effect tended to refine the net-frame structure and water flow path, leading to an increase in the efficiency of vacuum preloading. When exceeding the optimal amount, overdosage of flocculants resulted in the clogging of PVDs due to large cemented soil particles, reducing the vacuum transmission rate inside the slurry. Hence, the after-treatment soil strength decreased with flocculants’ amount when it is higher than the optimal value.

Copyright: © Jin-Kai Yan et al.
License:

Cette oeuvre a été publiée sous la license Creative Commons Attribution 4.0 (CC-BY 4.0). Il est autorisé de partager et adapter l'oeuvre tant que l'auteur est crédité et la license est indiquée (avec le lien ci-dessus). Vous devez aussi indiquer si des changements on été fait vis-à-vis de l'original.

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  • Reference-ID
    10536064
  • Publié(e) le:
    01.01.2021
  • Modifié(e) le:
    02.06.2021