Improvement of soft clay at a site in the Mekong Delta by vacuum preloading

Quang, Nguyen Duy; Giao, Pham Huy

doi:10.12989/gae.2014.6.5.419

Cited by 9 publications

(5 citation statements)

References 22 publications

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“…e unconfined compressive strengths of cement-treated soil (S-C) and cement-GGBFS-treated soil (C-F-S) range from 648 to 951 kPa and from 1539 to 2816 kPa, respectively. e lowest value of unconfined compressive strength is found in a specimen that has the smallest cement content (250 kg/m 3 ). e highest one is observed in the specimen that has the highest cement content (350 kg/m 3 ).…”

Section: Effect Of Binder Content On the Unconfined Compressivementioning

confidence: 96%

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An Experimental Study on Unconfined Compressive Strength of Soft Soil‐Cement Mixtures with or without GGBFS in the Coastal Area of Vietnam

Truong

Thanh

2020

Advances in Civil Engineering

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Soft soil is widely distributed in Vietnam, especially in the coastal area. In engineering practice, soft soil cannot be used to build any construction and needs to be improved or treated before building construction. In addition, Vietnam has many pig-iron or thermal power plants, which annually produce a huge amount of granulated blast furnace slag (GBFS). Thus, the use of this material for soft soil improvement needs to be considered. This paper presents experimental results on the unconfined compressive strength (UCS) of three Vietnam’s soft soils treated with Portland cement and Portland cement with ground granulated blast furnace slag (GGBFS). Binder dosage used in this study is 250, 300, and 350 kg/m3 with the three different water/cement ratios of 0.8, 0.9, and 1.0, respectively. The research results showed that the UCS of soil-cement mixtures depends on soil type, water/cement ratio, cement type, and binder content. Accordingly, the unconfined compressive strength increased with the increase of binder contents, the decrease of the natural water content of soft soil, water/cement ratios, and clay content. The highest value of UCS of treated soils was found for the soil at Site II with the Portland cement content, cement GGBFS, and water/cement ratio of 873 kg/m3, 2355 kg/m3, and 0.8, respectively. Besides, for all the three soils and two binder types, the water/cement ratio of 0.8 was found to be suitable to reach the highest UCS values of treated soil. The research results also showed that the UCS of treated soil with cement GGBFS was higher than that of treated soil with Portland cement. This indicated the effectiveness of the use of Portland cement with GGBFS in soft soil improvement. There is great potential for reducing the environmental problems regarding the waste materials from pig-iron plants in Vietnam and the construction cost as well.

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Section: Effect Of Binder Content On the Unconfined Compressivementioning

confidence: 96%

“…e stratigraphy of these deltas is very complicated and is formed in the Holocene age, that is, young sediments. ese sediments are mainly in soft to very soft state and often make an unfavorable condition for construction activities [1][2][3][4][5][6]. Recently, the demand for infrastructure development in Vietnam is on the rise.…”

Section: Introductionmentioning

confidence: 99%

An Experimental Study on Unconfined Compressive Strength of Soft Soil‐Cement Mixtures with or without GGBFS in the Coastal Area of Vietnam

Truong

Thanh

2020

Advances in Civil Engineering

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“…These projects include land reclamation projects and subgrade projects in which the soil mass needs to be strengthened. The technique is low cost, requires a short period to complete construction, requires no filling materials, involves no heavy machinery, and provides good reinforcement [1][2][3][4][5][6][7]. Regardless, the traditional vacuum preloading (TVP) method still has several disadvantages: On the one hand, under the action of vacuum pressure and water flow, fine soil particles gradually migrate to the vicinity of the prefabricated vertical drainage pipe, forming a low-permeability layer near the drainage pipe.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Effectiveness of the Step Vacuum Preloading Method: A Case Study on High Clay Content Dredger Fill in Tianjin, China

Chen

Yuan

et al. 2020

JMSE

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As a solution to avoid the blockage of the drainage pipe by traditional vacuum preloading, step vacuum preloading (SVP) has been progressively studied. However, the effectiveness of this technique has yet to be systematically analyzed. In this study, an indoor model test was conducted in which vacuum pressure was applied in five stages (10, 20, 40, 60, and 80 kPa) to dredger soil with high clay content at a reclamation site in Binhai New Area, Tianjin, China. The extent of the consolidation effect of the soil was determined, and the effectiveness of the step vacuum preloading method to address drainage pipe blockage was evaluated. The results indicate that soil settlement increases at each stage of vacuum pressure treatment and the degree of vertical consolidation at each stage exceeds 90%. At the end of the treatment stage with vacuum pressure of 80 kPa, the weakly bound water was discharged. Dissipation of pore water pressure occurred in all stages. On the basis of these results, it is shown that SVP can efficiently reinforce dredger fill. Moreover, after SVP, the grain size of the soil and void ratio are still uniformly distributed. Regardless of their location from the drainage pipe, soil exhibits permeability coefficients within the same order of magnitude. The consolidation effect of soil in each stage and the increased drainage rate in the initial stage of vacuum preloading with 80 kPa indicate that the test in the current study can decrease the horizontal displacement of fine particles and can avoid drainage pipe blockage.

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“…e sludge dewatering process [15] is shown in Figure 2, and the consolidation process of vacuum preloading drainage [16,17] is shown in Figure 3. e vacuum preloading drainage consolidation method has been widely used in many projects [18][19][20][21], and the vacuum preloading method has been gradually introduced into sludge treatment in sludge landfills for sludge drainage and consolidation treatment [22][23][24]. However, the largest problem of vacuum preloading drainage and consolidation is that the drainage channel is silted up.…”

Section: Introductionmentioning

confidence: 99%

Test and Analysis of Sludge Dewatering with a Vacuum Negative Pressure Load at the Bottom of Full Section

Wang

Jiang

et al. 2020

Advances in Civil Engineering

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At present, the sludge production has increased sharply, and sludge treatment remains a serious problem. Rapid sludge dewatering is the key problem of sludge treatment, and the main approach for reducing the cost of the sludge treatment is to reduce the cost of sludge dewatering. In this paper, two groups of sludge dewatering tests were carried out using homemade instruments and equipment. One group was conducted without rice straw, and the other group was conducted with rice straw. The relevant mechanism was analyzed, and the results indicate that sludge dewatering with a vacuum negative pressure load of the full section at the bottom is better than mechanical sludge dewatering. The sludge dewatering effect with rice straw is better than that without rice straw. Additionally, the vacuum degree inside the sludge decreased sharply. The pore water pressure slowly dissipates during the early and late stages and quickly during the middle stage. Sludge pore water seepage does not obey Darcy’s law, and sludge dewatering is intermittent.

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Improvement of soft clay at a site in the Mekong Delta by vacuum preloading

Cited by 9 publications

References 22 publications

An Experimental Study on Unconfined Compressive Strength of Soft Soil‐Cement Mixtures with or without GGBFS in the Coastal Area of Vietnam

An Experimental Study on Unconfined Compressive Strength of Soft Soil‐Cement Mixtures with or without GGBFS in the Coastal Area of Vietnam

Analysis of the Effectiveness of the Step Vacuum Preloading Method: A Case Study on High Clay Content Dredger Fill in Tianjin, China

Test and Analysis of Sludge Dewatering with a Vacuum Negative Pressure Load at the Bottom of Full Section

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