Vacuum Preloading Techniques — Recent Developments and Applications

Chu, Jian; Yan, Singapore S.; Indraratna, Buddhima

doi:10.1061/40971(310)73

Cited by 32 publications

(31 citation statements)

References 12 publications

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“…When a vacuum pressure is applied, the total stress remains the same but a decrease in the pore pressure by p a causes a corresponding increase in the mean effective stress (˜p9) to occur. Accounting for vacuum pump efficiency (ç), normally 70-80% of atmospheric pressure (Chu et al, 2008) p9 ¼ çp a…”

Section: Theorymentioning

confidence: 99%

“…PVDs serve a dual purpose during vacuum consolidation in that they aid in the balanced distribution of vacuum pressure over the soil treatment depth while also discharging extracted pore water up to the permeable soil cushion at ground surface level (Chu et al, 2008). As they have become cheaper, flexible PVDs have generally replaced sand drains and granular piles (Dam et al, 2006;Indraratna, 2010 Design charts for vertical drains were developed by Rujikiatkamjorn and Indraratna (2007) in order to estimate an appropriate drain spacing, considering a larger range of soil properties and drain installation patterns.…”

Section: Pvdsmentioning

confidence: 99%

“…This occurs because the vacuum treatment would need to be performed consecutively for different sub-areas, although this approach leads to inefficiencies (Chu et al, 2008). This challenge may be overcome by connecting the vacuum line directly to each individual PVD using a tubing system, such as that proposed by Seah (2006) (Figure 3).…”

Section: Field Investigationmentioning

confidence: 99%

“…Inter-bedded, more permeable layers can also produce some practical problems. Wrapping an impermeable plastic sleeve around each PVD, over the depth of the more permeable layer, is one solution, but the adoption of this approach in practice requires precise knowledge of the subsoil strata (Chu et al, 2008).…”

Section: Field Investigationmentioning

confidence: 99%

“…The vacuum pump produces a negative pressure (with respect to atmospheric pressure) in the permeable soil cushion, located immediately beneath the sealing membrane, and along PVDs installed within (Chu et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Ground improvement by vacuum consolidation – a review

Griffin

O’Kelly

2014

Proceedings of the Institution of Civil Engineers - Ground Impr

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This paper presents a review of literature related to the vacuum consolidation ground improvement technique, focusing on issues affecting efficiency of performance and the application of the technique in peaty ground.Although it is now widely considered to be effective for reducing post-construction settlement, studies on vacuum consolidation in peat have, to date, mostly been limited to field trials. This paper offers an overview of the development and theory behind the technique. Issues affecting the efficiency of vacuum systems and recent advances in predicting the ground response to vacuum preloading are described. The application of the technique in peaty soils is investigated; an overview is also provided of some geotechnical properties that distinguish peat from soft mineral soils, highlighting lessons learned from relevant case studies.

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Section: Theorymentioning

confidence: 99%

Section: Pvdsmentioning

confidence: 99%

Section: Field Investigationmentioning

confidence: 99%

Section: Field Investigationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Ground improvement by vacuum consolidation – a review

Griffin

O’Kelly

2014

Proceedings of the Institution of Civil Engineers - Ground Impr

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One‐dimensional self‐weight consolidation with continuous drainage boundary conditions: Solution and application to clay‐drain reclamation

Feng

Mei

2019

Num Anal Meth Geomechanics

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Summary Traditional consolidation theories cannot provide good predictions of consolidation settlement in land reclamation because of their assumptions that the influence of soil's self‐weight is often neglected, and the drainage boundary is considered as fully pervious/impervious. In view of these limitations, an analytical solution is derived for one‐dimensional self‐weight consolidation problems with a continuous drainage boundary using the finite Fourier sine transform method. Following the classical Terzaghi's small strain theory, the soil's self‐weight is considered to produce consolidation settlement in dredged materials with a constant coefficient of consolidation. The continuous drainage boundary can essentially describe the time‐dependent variation of drainage capacity at the interface between two adjacent soil layers. By reducing the interface parameters, the effectiveness of the calculation is demonstrated against the Terzaghi's solution. The influence of interface parameters and soil's self‐weight stress coefficient on self‐weight consolidation is discussed. As expected, the rate of consolidation considering the self‐weight stress is faster, although the dependency of consolidation rate on the material property of void ratio is neglected. Moreover, the plane of maximum excess pore‐water pressure is estimated as a function of time factor, based on which a design chart is developed to optimize the layout of horizontal drains in land reclamation.

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Large‐strain consolidation of vacuum preloading combined with partially penetrating prefabricated vertical drains

Guo,

Zhou,

Sun

et al. 2024

Num Anal Meth Geomechanics

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A system of vacuum preloading combined with partially penetrating prefabricated vertical drains (PP‐PVDs) is an effective solution for promoting the consolidation of the dredged marine clay. However, a significant and traditionally challenging‐to‐predict amount of deformation or settlement occurs. Therefore, it is necessary to introduce a three‐dimensional large‐strain consolidation model to consider the length of the vertical drain to determine the consolidation time and degree of consolidation (DoC), and associated settlement. The predictions using the proposed analytical model provide fair agreements with the field data and those in the literature. Parametric studies reveal that to achieve a 90% DoC within 100 days in soft soil, the optimal penetration depth for PP‐PVDs would be 0.7 times the depth of the soil layer. With the increase of DoC, the ratio of excess pore water pressure to applied vacuum pressure (u/P) in the whole soil layer moves toward 1.0. With the increase of PVD penetration ratio (H1/H), more DoC is required to dissipate the excess pore water pressure in the top improved soil layer.

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Vacuum Preloading Techniques — Recent Developments and Applications

Cited by 32 publications

References 12 publications

Ground improvement by vacuum consolidation – a review

Ground improvement by vacuum consolidation – a review

One‐dimensional self‐weight consolidation with continuous drainage boundary conditions: Solution and application to clay‐drain reclamation

Large‐strain consolidation of vacuum preloading combined with partially penetrating prefabricated vertical drains

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