Application of a Modified Vacuum Preloading Method on a Dredged Fill Soft Foundation

2012 ◽  
Vol 170-173 ◽  
pp. 3130-3134 ◽  
Author(s):  
Yun Liang Cui ◽  
Ming Jun Gao ◽  
Zhi Hao Liu
Keyword(s):  
Bearing Capacity ◽  
Reinforcement Effect ◽  
Large Area ◽  
Vacuum Preloading ◽  
Soft Foundation ◽  
Short Period ◽  
Dredging Sludge ◽  
Made In China ◽  
Preloading Method ◽  
Sand Cushion

A lot of large area lands were made in China coastal areas by dredging sludge from the sea. The dredged fill ground had a very low bearing capacity which should be increased as soon as possible to meet the requirements of constructions. However, conventional vacuum preloading could not be used for this purpose because the sand cushion could not be laid on the sludge ground due to the very low bearing capacity. To solve this problem, a modified vacuum preloading method without sand cushion was proposed. This method has been successfully tested and applied in the reclamation project in Wenzhou. Based on this project, the technological process and the key technology were introduced and the reinforcement effect was analyzed. Project results showed the modified vacuum preloading method could achieve a good reinforcement effect on large area dredged fill ground in a short period. It is worth to promote the application of this method in coastal reclamation projects.

No-sand cushion vacuum preloading method to improve bearing capacity of fresh hydraulic fill mud

2016 ◽  
pp. 455-459
Author(s):  
Wei Bai ◽  
Rong-Bing Lin ◽  
Dong-Liang Zhu ◽  
Zhu-Xiong Liu ◽  
Guan-Fu Yuan
Keyword(s):  
Bearing Capacity ◽  
Vacuum Preloading ◽  
Hydraulic Fill ◽  
Preloading Method ◽  
Sand Cushion

scholarly journals Design Method and Verification of Electroosmosis-Vacuum Preloading Method for Sand-Interlayered Soft Foundation

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Yunliang Cui ◽  
Jianbo Tu ◽  
Xinquan Wang ◽  
Hongguo Diao ◽  
Qianru Ge
Keyword(s):  
Design Method ◽  
Simulation Method ◽  
Electrical Circuit ◽  
Test Results ◽  
Vacuum Preloading ◽  
Foundation Treatment ◽  
Vertical Drain ◽  
Soft Foundation ◽  
Prefabricated Vertical Drain ◽  
Preloading Method

The design method of electroosmosis-vacuum preloading for soft foundation treatment is not systematic and complete, thereby restricting the application of the technology in engineering. A design method for the electroosmosis-vacuum preloading treatment of sand-interlayered soft foundation is therefore presented. A compressible electrical prefabricated vertical drain is developed, and a vacuum sealing and draining system is designed for the application of the electroosmosis-vacuum preloading in sand-interlayered soft foundation. Calculation formulas of site resistance considering the interlayer and interface resistivity of the electrode are established to design the power supply and electrical circuit. A simple numerical simulation method is proposed to predict the ground settlement treated by electroosmosis-vacuum preloading. A field test of electroosmosis-vacuum preloading is designed using the suggested method, and comparison tests between the electroosmosis-vacuum preloading and the vacuum preloading are performed to verify the proposed technique. The test results show that the proposed design method is reasonable for the design of electroosmosis-vacuum preloading in engineering.

Test Study on Effective Reinforcement Depth of Dynamic Compaction and Filling Replacement

2011 ◽  
Vol 368-373 ◽  
pp. 2550-2553 ◽  
Author(s):  
Wei Li ◽  
Chun Xiao Zhang ◽  
Peng Xiang Sun
Keyword(s):  
Bearing Capacity ◽  
Low Cost ◽  
Soft Soil ◽  
Dynamic Compaction ◽  
Reinforcement Effect ◽  
Large Area ◽  
Remarkable Effect ◽  
Ground Treatment ◽  
Test Study ◽  
Effective Reinforcement

Filling replacement combined with dynamic compaction is a very effective method to preprocess the soft soil to obtain larger bearing capacity. That not only has remarkable effect to improve soil bearing capacity, but also has some advantages, such as quick construction, simple equipment, low cost and so on. And that is appropriate for large area ground treatment engineering. The purpose of ensuring the reinforcement effect and saving the project cost, and providing references for the similar projects can be achieved through the test study on effective reinforcement depth of dynamic compaction and filling replacement.

The Applied Research of Underwater Vacuum Preloading Method in Soft Soil Foundation

2014 ◽  
Vol 580-583 ◽  
pp. 742-745
Author(s):  
Yu Qin Feng ◽  
Lu Zhang
Keyword(s):  
Soft Soil ◽  
Soft Ground ◽  
Construction Technology ◽  
Engineering Project ◽  
Vacuum Preloading ◽  
Soft Foundation ◽  
Before And After ◽  
Soil Foundation ◽  
Soft Soil Foundation ◽  
Preloading Method

On the basis of engineering project using underwater vacuum preloading method to strengthening the soft foundation, under the specific geological conditionsthis article analyzes the construction technology and reinforcement mechanism of underwater vacuum preloading of the soft soil foundation. By indoor soil test of Reinforcement of soil before and after processing, compared the change and improve of soil shear strength indexes before and after the reinforcement, it is verified that the underwater vacuum preloading method is a effective mean in handing soft ground, and can be further promoted as a means of handling soft ground along the coastal area of China.

Application of Vacuum Preloading for Soft Foundation Treatment in Grain Storage

2012 ◽  
Vol 226-228 ◽  
pp. 1359-1364
Author(s):  
Qi Xia Liu ◽  
Yang Zhao
Keyword(s):  
Mechanical Performance ◽  
Soft Soil ◽  
Grain Storage ◽  
Vacuum Preloading ◽  
Obvious Effect ◽  
Ground Treatment ◽  
Foundation Treatment ◽  
Soft Foundation ◽  
Preloading Method ◽  
Design Construction

The application of vacuum preloading for soft foundation treatment in grain storage is introduced from its principle, design, construction and the inspections. Its obvious effect is proved by example. The vacuum preloading method can effectively improve the soft soil foundation’s physical and mechanical performance and increase the bearing capacity of soft soil of coastal areas. For the grain storage, oil depot especially for large reserves of oil depot project, the treatment effect is remarkable. It can be widely used in the ground treatment in the soft soil area for grain storage, oil depot construction.

Slurry Improvement by Direct Drainage Vacuum Preloading Method

2015 ◽  
Vol 744-746 ◽  
pp. 589-592
Author(s):  
Y.Z. Bai ◽  
Jian Chen ◽  
Bei Cheng
Keyword(s):  
Soil Depth ◽  
Soil Surface ◽  
Vacuum Preloading ◽  
Vertical Drain ◽  
Prefabricated Vertical Drain ◽  
Horizontal Drainage ◽  
Stabilized Soil ◽  
Drainage Effect ◽  
Preloading Method ◽  
Sand Cushion

Traditional vacuum preloading method has two drainage parts: 1) horizontal drainage part-sand cushion; 2) vertical drainage part-(Prefabricated vertical drain (PVD) and so on). During vacuum preloading process, the drainage effect of horizontal sand cushion is strong near stabilized soil surface and decreases rapidly at deeper position, while drainage range of vertical drain includes whole stabilized soil depth and its drainage ability is higher. So, it is important to improve the drainage design of vacuum preloading system to transmit vacuum head to vertical drain more efficiently. This paper presents a new vacuum preloading method-direct drainage vacuum preloading method (DDVP method). Compared with traditional vacuum preloading method, this system cancels horizontal drainage part-sand cushion and uses sealed pipe to directly connect with PVDs. Vacuum head can be transmitted into PVD without attenuation. Field test is applied to study the effect of slurry improvement of this method.

Laboratory Model Tests on Dredger Fills by Vacuum Preloading with No Sand Cushion

2012 ◽  
Vol 170-173 ◽  
pp. 655-660
Author(s):  
Ya Jun Wu ◽  
Jian Bo Yang
Keyword(s):  
Fine Particles ◽  
Soil Strength ◽  
Plasticity Index ◽  
Laboratory Model ◽  
Soil Parameters ◽  
Grain Composition ◽  
Vacuum Preloading ◽  
Prefabricated Vertical Drains ◽  
Water Contents ◽  
Sand Cushion

It is difficult to operate on the hydraulic-filled mucky soil foundation which the water content is high, so the vacuum preloading method with no sand cushion is used to deal with the foundation in some areas in China. Although there are still many problems in it’s application, such as, the effective range of the prefabricated vertical drains(PVDs) is small, the surrounding soil is easy to be accumulated and the soil strength increases little. For these problems, a laboratory model test on dredger fills made from the 4th layer of the Shanghai mucky soil by vacuum preloading with no sand cushion is performed. The changes and distributions in the settlement, water contents, permeability, plasticity index and grain composition of the dredger fill are studied in the process of the vacuum preloading. It is found that the water contents and permeability of the soft clay near the PVD (the diameter is about 40 to 50cm) are much lower than the outside, while the content of fine particles, plasticity index and soil strength near the PVD is much higher than the others. The measured data shows that the fine particles gather to a soil column at the center of the PVD under the action of vacuum negative pressure, then the permeability and the grain composition of the soil around the PVD is changed. As a result, soil parameters are not evenly distributed. Finally, some suggestions about how to reduce the non-uniformity are proposed.

Vacuum preloading consolidation of reclaimed land: a case study

1998 ◽  
Vol 35 (5) ◽  
pp. 740-749 ◽  
Author(s):  
J Q Shang ◽  
M Tang ◽  
Z Miao
Keyword(s):  
Land Reclamation ◽  
Soil Improvement ◽  
Large Area ◽  
Vacuum Preloading ◽  
Reclaimed Land ◽  
Improvement Project ◽  
Prefabricated Vertical Drains ◽  
Vertical Drains ◽  
Soft Clays

This case study presents the design, operation, and results of a soil improvement project using the vacuum preloading method on 480 000 m2 of reclaimed land in Xingang Port, Tianjing, China. The areas treated with vacuum ranged from 5000 to 30 000 m2. The effects of soil improvement are demonstrated through the average consolidation settlement of 2.0 m and increases in undrained shear strengths by a factor of two to four or more. The study shows that the vacuum method is an effective tool for the consolidation of very soft, highly compressive clayey soils over a large area. The technique is especially feasible in cases where there is a lack of surcharge loading fills, extremely low shear strength, soft ground adjacent to critical slopes, and access to a power supply.Key words: vacuum preloading consolidation, soil improvement, soft clays, land reclamation, prefabricated vertical drains.

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