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

Sun, Honglei; He, Zili; Pan, Kun; Lu, Jingling; Pan, Xiaodong; Shi, Li; Geng, Xueyu

doi:10.1139/cgj-2021-0248

Cited by 8 publications

(9 citation statements)

References 41 publications

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“…As shown in Figure 2, a cuboid aluminium model testing box with an internal dimension of 870 mm (length) × 160 mm (width) × 620 mm (height) was made for the laboratory tests. Silicon grease was smeared onto the inner wall of the case to reduce the friction between the soil and the model walls (Sun et al, 2022b). The front wall of the testing box consisted of a Perspex window with a thickness of 45 mm, in which control points for optimizing the photogrammetric transformation parameters were set (White et al, 2003).…”

Section: Testing Apparatusmentioning

confidence: 99%

“…The front wall of the testing box consisted of a Perspex window with a thickness of 45 mm, in which control points for optimizing the photogrammetric transformation parameters were set (White et al, 2003). To minimize friction between the Perspex window and slurry sample, the window was polished and then flanged to the testing box (Sun et al, 2022b). The top of the box was sealed with a polyvinyl chloride (PVC) membrane to ensure airtightness during vacuum preloading.…”

Section: Testing Apparatusmentioning

confidence: 99%

“…Many studies discussed the formation of soil columns and also proposed methods such as pretreating the slurry (Wang et al, 2017a;Wang et al, 2017b;Sun et al, 2022c), step vacuum preloading (Fang et al, 2019), and reducing PVD spacing (Tang et al, 2010;Wu et al, 2021) to reduce the clogging. In addition, Fang et al (2019); Zhou et al (2021); Sun et al (2022a); Sun et al (2022b), and Shen (2018) used particle size distribution, soil sample water content distribution, vane shear strength along the radial direction and particle image velocimetry (PIV) technology to determine the thickness of the clogging zone to be 40-100 mm under a single-PVD model test. As the formation of the clogging zone is the result of the accumulation of soil particles near PVD (Sun et al, 2022a;Sun et al, 2022b), with the gradual transfer of vacuum pressure from PVD to far field during consolidation, the effect of PVD layout on the displacement of soil particles will further impact the formation of the clogging zone.…”

mentioning

confidence: 99%

“…In addition, Fang et al (2019); Zhou et al (2021); Sun et al (2022a); Sun et al (2022b), and Shen (2018) used particle size distribution, soil sample water content distribution, vane shear strength along the radial direction and particle image velocimetry (PIV) technology to determine the thickness of the clogging zone to be 40-100 mm under a single-PVD model test. As the formation of the clogging zone is the result of the accumulation of soil particles near PVD (Sun et al, 2022a;Sun et al, 2022b), with the gradual transfer of vacuum pressure from PVD to far field during consolidation, the effect of PVD layout on the displacement of soil particles will further impact the formation of the clogging zone. Compared with the extensive studies focused on the thickness of the clogging zone, few studies have investigated the clogging zone development, especially the development under different PVD layouts.…”

mentioning

confidence: 99%

“…Compared to traditional displacement measurement methods, PIV offers higher accuracy and the advantage of full-field measurement (White et al, 2003;White and Bolton, 2004;Wang et al, 2021). With the advancement of photography and algorithms, PIV technology has been more widely used in geotechnical tests, such as vacuum preloading model tests (Jiang et al, 2020;Sun et al, 2022a;Sun et al, 2022b), cone penetration tests (White and Bolton, 2004;Arshad et al, 2014) and undrained cyclic torsional shear tests (Zhao et al, 2020). These cases rely on an artificial texture when modelling fine-grained soils, which provides the basis for this research.…”

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confidence: 99%

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

Cai

et al. 2023

Front. Mar. Sci.

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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.

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Section: Testing Apparatusmentioning

confidence: 99%

Section: Testing Apparatusmentioning

confidence: 99%