Experimental study on the clogging effect of dredged fill surrounding the PVD under vacuum preloading

Numerical Simulation of Vacuum Preloading for Chemically Conditioned Municipal Sludge

“…The decrease in the water content resulted in a relatively low permeability layer. This phenomenon of low permeability layer was also observed in the vacuum preloading process of the dredged fill with high water content [32]. Due to the high water content of the conditioned sludge, the soil particles were in a fluid state.…”

“…Also, the deformation of each element was consistent but it was different from the actual deformation. In the actual vacuum preloading process, the sludge near the prefabricated vertical drain was consolidated first and the water content decreased, thereby forming a relatively low permeability layer, which slowed down the whole drainage consolidation process [32]. At the same time, due to the interaction between the sludge units, the sludge around the prefabricated vertical drain settled one after the other, and the actual deformation of the sludge layer was closer to that based on equal strain.…”

Analytical solutions for consolidation of soft soil improved by air‐boosted vacuum preloading considering clogging effect

“…First of all, the vacuum pressure dissipates with time and depth, such situation will not only result in ineffective consolidation of deep soil, but lower vacuum pressure can also lead to a longer construction period. What's more, the performance of prefabricated vertical drains (PVDs) in drainage can be adversely affected by clogging since the dredged slurry is the main fill material for land reclamation projects 11,12 . Fine clay particles would accumulate at the filter membrane of the PVDs inevitably as consolidation proceeds, which results in a significant decrease in the permeability of PVDs 13 .…”

“…What's more, the performance of prefabricated vertical drains (PVDs) in drainage can be adversely affected by clogging since the dredged slurry is the main fill material for land reclamation projects. 11,12 Fine clay particles would accumulate at the filter membrane of the PVDs inevitably as consolidation proceeds, which results in a significant decrease in the permeability of PVDs. 13 The clogging effect can even stop the consolidation process despite extended construction time, which would also result in insufficient consolidation of the ground.…”

A vertical and radial consolidation analysis incorporating drain degradation based on the spectral method

“…Physical factors such as clogging due to fine silt intrusion, large strain deformation, the potential kinking and bending (Deng et al 2013a;2013bKim et al 2018;Tran-Nguyen et al 2010;Xu et al 2020), and bio-chemical factors such as bacterial activity, high organic and acidic environment (Indraratna et al 2016;Kim and Cho 2008;Nguyen et al 2018aNguyen et al , 2018b can cause a considerable reduction in the discharge capacity of drains with time. For instance, Chai and Miura (1999), Kim and Cho (2008), Kim et al (2011), Bo et al (2016) and Nguyen et al (2018a) investigated the retarded capacity discharge of PVDs over time by laboratory tests, while some other field data (Bergado et al 1996) showed considerable retardation of the consolidation curves at deeper layers, where the discharge capacity of drains has decreased.…”