Combination of vacuum preloading and lime treatment for improvement of dredged fill

Wang, Jun; Ni, Junfeng; Cai, Yuanqiang; Fu, Hongtao; Wang, Peng

doi:10.1016/j.enggeo.2017.02.013

Cited by 121 publications

(28 citation statements)

References 28 publications

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“…Deng et al (2009) proposed a ventilating vacuum method, aiming to solve the large pressure gradient to restrain the clogging effect. Wu et al (2017) and Wang et al (2017) introduced chemical additives (anionic, cationic, and neutral polyacrylamide) into the HRM ground and found that the additives can effectively enhance the improvement quality as the solid-liquid separation and the generation of the flocculants ameliorates the percolation property of the surrounding soils.…”

Section: Introductionmentioning

confidence: 99%

Colloid effect on clogging mechanism of hydraulic reclamation mud improved by vacuum preloading

et al. 2019

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Many cases of artificial soft clay foundation constructed by hydraulic filling and improved by the vacuum preloading show the clogging phenomenon in the surrounding soil, which compromises the improvement quality. To clarify the clogging mechanism and the formation of soil columns, the vacuum process was tracked from macro to micro by laboratory model tests. Results show that the soil column with higher strength (density) and lower water content was formed surrounding the prefabricated vertical drainage (PVD). Mercury intrusion porosimetry (MIP) tests revealed that the pore-entrance diameter of the soil column after 50 and 43 days of vacuum application ranged from 100 to 600 nm, and that at peak it is 300 nm. However, the mean diameter of the colloidal particles in tail water decreases from 1000 to 100 nm with continuous vacuum application, and then becomes stable at about 100 nm after 43 days. After re-visiting the vacuum process of the hydraulic reclamation mud, the pore-size distribution of surrounding soils and particle-size distribution of the tail water, the clogging was explained by the filling of the pores of the soil column by the colloidal particles in pore water. This mechanism differentiates the artificial foundation improved by vacuum preloading from the natural foundation for the presence of rich colloidal particles in pore water.

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Section: Introductionmentioning

confidence: 99%

Colloid effect on clogging mechanism of hydraulic reclamation mud improved by vacuum preloading

et al. 2019

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“…At a depth of 0.6 m, the measurement time was 372 h for T1 and 246 h for T2, and the corresponding times required to reach stable pressure values were about 700 and 600 h, respectively, as di erent vacuum levels within the soil were achieved within the same period at various depths [25]. e obtained measurement times indicate that the soil was in an unsaturated state and that the existence of the unsaturated zone during preloading accelerated the increase in the subsoil vacuum pressure and raised the maximum pressure limit [26]. Hence, it can be concluded that, at the same depth of the improved soil, the longer PVDs can induce an earlier appearance of the unsaturated zone followed by the achievement of a steady vacuum pressure (as compared with the e ects produced by the shorter PVDs).…”

Section: Testing Procedure Testing Was Performed As Followsmentioning

confidence: 93%

Consolidation Effect of Prefabricated Vertical Drains with Different Lengths for Soft Subsoil under Vacuum Preloading

Lou

Chai

et al. 2019

Advances in Civil Engineering

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The application of vacuum preloading to prefabricated vertical drains (PVDs) with different lengths is widely used in practical engineering to investigate their consolidation at the same depths of even and multilayer subsoils from the seabed. In a laboratory, model experiment was conducted using even subsoil and embedded PVDs with lengths of 0.6 and 1.2 m. The obtained results showed that in the even subsoil, the 1.2 m PVDs maintained a higher vacuum pressure in the shallow layer and demonstrated better consolidation behavior as compared to those of the 0.6 m PVDs. In the upper subsoil layer, the average vane shear strengths of these two systems increased to 18.2 and 22.6 kPa, respectively. The degree of consolidation of the upper subsoil layers in the two model experiments calculated from the pore water pressures under boundary drainage conditions were 51% and 68%, respectively. For practical verification purposes, similar experiments were conducted for multilayer subsoil by inserting PVDs with lengths of 6 and 15 m into different test sites. As a result, the vane shear strengths of the upper 6 m subsoil layers increased to 26.3 and 33 kPa, while the degree of consolidation were 72.1% and 80.9%, respectively, although some irregularities were observed at different depths.

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“…Moreover, soil properties in the clogging zone and outside the zone varied in many aspects. The proportion of fine particles in the clogging zone was greater than that outside the zone (Wang et al, 2017;Deng et al, 2018;Fang et al, 2019). Those fine particles filled the pores of the soil, reducing compressibility in the clogging zone.…”

Section: Introductionmentioning

confidence: 97%

Consolidation Considering Clogging Effect under Uneven Strain Assumption

et al. 2021

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Combination of vacuum preloading and lime treatment for improvement of dredged fill

Cited by 121 publications

References 28 publications

Colloid effect on clogging mechanism of hydraulic reclamation mud improved by vacuum preloading

Colloid effect on clogging mechanism of hydraulic reclamation mud improved by vacuum preloading

Consolidation Effect of Prefabricated Vertical Drains with Different Lengths for Soft Subsoil under Vacuum Preloading

Consolidation Considering Clogging Effect under Uneven Strain Assumption

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