Influence of prefabricated vertical drains spacing on FeCl3-vacuum consolidation of a landfill sludge

Vacuum preloading combined with prefabricated vertical drains (PVDs) has the potential to improve the soft sediments under water, however, its development is partly limited by the unclear understanding of the mechanism. This paper aims to extend the comprehension of the influential mechanism of overlapping water in the scenario of underwater vacuum preloading with PVDs. The systematic investigations were conducted by small strain finite element drained analyses, with the separated analysis schemes considering suction-induced consolidation, seepage and their combination. The development of settlement in the improved soil region and the evolution of seepage flow from the overlapping water through the non-improved soil region into improved zone are examined in terms of the build-up of excess pore pressure. Based on the results of numerical analyses, a theoretical approach was set out. It was capable to estimate the time-dependent non-uniform settlement along the improved soil surface in response to the combined effects of suction-induced consolidation and seepage. The difference of underwater and onshore vacuum preloading with PVDs is discussed with some practical implication and suggestion provided.

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Comparison of performance of single- and double-core prefabricated vertical drains for thick reclaimed ground improvement

Marine Georesources and Geotechnology ◽

10.1080/1064119x.2021.1903123 ◽

2021 ◽

pp. 1-13

Author(s):

Hyobum Lee ◽

Jeonghun Yang ◽

Minkyu Kang ◽

Sangwoo Park ◽

Hangseok Choi

Keyword(s):

Ground Improvement ◽

Prefabricated Vertical Drains ◽

Vertical Drains

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Recent Advances in Prefabricated Vertical Drains

Ports 2013 ◽

10.1061/9780784413067.091 ◽

2013 ◽

Author(s):

A. D. Goldberg ◽

M. A. Palmatier

Keyword(s):

Prefabricated Vertical Drains ◽

Vertical Drains ◽

Recent Advances

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Consolidation of cement-treated sewage sludge using vertical drains

Canadian Geotechnical Journal ◽

10.1139/t04-114 ◽

2005 ◽

Vol 42 (2) ◽

pp. 528-540 ◽

Cited By ~ 19

Author(s):

J Chu ◽

M H Goi ◽

T T Lim

Keyword(s):

Sewage Sludge ◽

Land Reclamation ◽

Model Tests ◽

Waste Materials ◽

Test Results ◽

Prefabricated Vertical Drains ◽

Vertical Drains ◽

Treated Sewage ◽

The World

The disposal of sewage sludge and other waste materials has become a problem in many cities around the world. A study on the use of sewage sludge and other waste materials for land reclamation has been conducted. One of the methods studied is to dispose of the sludge after it has been mixed with binders or other waste materials and then to consolidate the mixture on site using surcharge and prefabricated vertical drains (PVDs). To study the consolidation behaviour of the sludgebinder mixtures around PVDs, model tests using a fully instrumented consolidation tank were conducted. Some of the test results are presented in this paper. The study shows that PVDs are effective in consolidating the sludge and binder mixtures, provided that the PVDs used can sustain large bending and resist corrosion by the chemicals in the sludge.Key words: consolidation, geoenvironmental, land reclamation, prefabricated vertical drains.

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Ground settlement prediction of embankment treated with prefabricated vertical drains in soft soil

MATEC Web of Conferences ◽

10.1051/matecconf/201819503014 ◽

2018 ◽

Vol 195 ◽

pp. 03014

Author(s):

Siswoko Adi Saputro ◽

Agus Setyo Muntohar ◽

Hung Jiun Liao

Keyword(s):

Numerical Study ◽

Soft Soil ◽

Soil Permeability ◽

K Value ◽

Prefabricated Vertical Drains ◽

Vertical Drains ◽

Prefabricated Vertical Drain ◽

Actual Settlement ◽

Final Settlement ◽

Best Fit

Excessive settlement due to consolidation can cause damage to the structure’s rest on soft soil. The settlement takes place in relatively longer. The preloading and prefabricated vertical drain (PVD) is often applied to accelerate the primary settlement. The issue in this research is the estimation of the settlement. The Asaoka method and the finite element method using PLAXIS-2D are used to estimate the final settlement of a PVD treated embankment. For the former, a complete record of the settlement was required; for the latter, some ground parameters are needed for the PLAXIS-2D analysis, such as the permeability of the soil. Because the installation process of PVD tends to influence the permeability of the in-situ soil around the PVD, the soil permeability after the installation of PVD needs to be adjusted. The numerical results were compared with actual settlement data to find out the best-fit input parameters (i.e. soil permeability) of the actual data. It was found that the best-fit soil permeability (k) used in the numerical study was about one-half of the k value determined from the laboratory test. The Root Mean Square Deviation shows that the settlement predicted by the numerical analysis has approximately 30% of the actual settlement.

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