Combined vacuum and surcharge preloading method to improve lianyungang soft marine clay for embankment widening project: A case

2020 ◽  
Author(s):  
Jun Wu ◽  
Youjin Xuan ◽  
Yongfeng Deng ◽  
Xingqi Li ◽  
Fusheng Zha ◽  
...  
Keyword(s):  
Marine Clay ◽  
Surcharge Preloading ◽  
Preloading Method

Soil improvement for a storage yard using the combined vacuum and fill preloading method

2005 ◽  
Vol 42 (4) ◽  
pp. 1094-1104 ◽  
Author(s):  
S.-W Yan ◽  
J Chu
Keyword(s):  
Ground Improvement ◽  
Soil Improvement ◽  
Undrained Shear Strength ◽  
Foundation Soil ◽  
Surcharge Preloading ◽  
Clay Slurry ◽  
Degree Of Consolidation ◽  
Preloading Method ◽  
Undrained Shear

This paper presents a case study of using the combined vacuum and fill surcharge preloading method to improve the foundation soil for a storage yard at Tianjin Port, China. A vacuum load of 80 kPa was applied for 4-8 weeks before fill surcharge was added in stages. The site to be improved was recently reclaimed using dredged clay slurry. Both the consolidated clay slurry fill and the seabed soils were very soft. After the combined vacuum and fill surcharge preloading, the ground settled more than 1 m. The average degree of consolidation achieved was more than 80%. The undrained shear strength of the soil increased twofold. The water content of the soil also decreased substantially. The soil improvement procedure using the combined vacuum and fill surcharge preloading method and the instrumentation scheme are described, the field monitoring data are presented and analyzed, and methods to estimate the degree of consolidation and several other issues related to the combined preloading method are discussed.Key words: case history, consolidation, ground improvement.

Quality Control Indexes Study of Vacuum Combined with Fill Surcharge Preloading Method

2012 ◽  
Vol 209-211 ◽  
pp. 1459-1462
Author(s):  
Shang Yu Han ◽  
Li Hong
Keyword(s):  
Vacuum Pressure ◽  
Soil Consolidation ◽  
Vertical Load ◽  
Foundation Soil ◽  
Load Pressure ◽  
Surcharge Preloading ◽  
Soil Settlement ◽  
Consolidation Effect ◽  
Preloading Method

The consolidation effect of vacuum combined with fill surcharge preloading always influenced by many factors including vacuum pressure, vertical load pressure and vertical drainage depth. As the way to improve the reliability of the method, based on the soil consolidation mechanisms and actual data getting from the laboratory test and in-situ test, the main indexes of the method were studied in this paper. The test results show that the ratio of the vacuum pressure and vertical load pressure can cause difference soil settlement-deformation, if the ratio close to 1 the consolidation effect of the foundation can be gradually advanced. The soil outside the embankment always has displacement to reinforcement region in the upper depth of the foundation soil when the vacuum pressure equals to the vertical load pressure.

On Ground Settlement Rate Approach of Preloading Method

2013 ◽  
Vol 353-356 ◽  
pp. 258-264
Author(s):  
Ming Lei Shi ◽  
Rui Kun Zhang ◽  
Hao Zhang
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Ground Settlement ◽  
Settlement Rate ◽  
Excess Pore Water Pressure ◽  
Surcharge Preloading ◽  
The Relationship ◽  
Preloading Method ◽  
Linear Compressibility ◽  
Excess Pore

Based on the theory of the Terzaghi 1-D consolidation and the linear compressibility of soil, a rational method for regionalization of recompression and compression in the distribution of the excess pore-water pressure under overloading-unloading was presented. A simple generalized expression of the ground settlement rate applied to insufficient-load preloading, equal-load preloading, surcharge preloading and a time expression of insufficient-load preloading, surcharge preloading relative to equal-load preloading were further derived. The relationship mechanism of settlement rate and time of insufficient-load preloading, surcharge preloading relative to equal-load preloading are discussed based on the same allowed post-construction settlement.

The Analysis of Vacuum-Surcharge Preloading Method with FLAC3D

2013 ◽  
Vol 405-408 ◽  
pp. 151-154
Author(s):  
Chun Yuan Liu ◽  
Song Shen ◽  
Jie Li ◽  
Peng Chao Zhang
Keyword(s):  
Soft Soil ◽  
Water Discharge ◽  
Soil Layer ◽  
Real Situation ◽  
Actual Measurement ◽  
A Value ◽  
Multi Stage ◽  
Surcharge Preloading ◽  
Foundation Deformation ◽  
Preloading Method

Based on the test section on the expressway in Jiangsu, the thesis makes a model and then conducts numerical simulation on the settlement of soft soil subgrade by using FLAC3D. The author set the filling layer null, and assigns a value to the loaded soil layer according to the construction sequence to realize multi-stage loading. The thesis also analyzes the pore water discharge and foundation deformation when the soil is consolidated. It shows that the simulation result is very close to actual measurement result, and can clearly demonstrate the real situation of settlement.

Case Study on Soft Foundation of Coastal Saline Soil

2014 ◽  
Vol 1065-1069 ◽  
pp. 469-474
Author(s):  
Jun Sun ◽  
Hai Jun Chen ◽  
Si Hai Wang ◽  
Hong Mei Li
Keyword(s):  
Membrane Separation ◽  
Saline Soil ◽  
Soil Layer ◽  
Coastal Saline Soil ◽  
Surcharge Preloading ◽  
Layer Composite ◽  
Vane Shear Test ◽  
Embankment Height ◽  
Soil Foundation ◽  
Preloading Method

Coastal saline soil foundation was consolidated by surcharge preloading method based on the improving constructio technol-ogy. For instance,setting sand gravels separation layer,composite geo-membrane separation layer,improve embankment height, etc. The monitoring results are analyzed including the ground with every soil layer settlement. Combining with the test result of the shear strength of vane shear test and various ion content of soil samples,it is concluded that reinforcement effect of seashore saline soil consolidated by surcharge preloading method,at the same time, exclusion salt and reduce damage of the foundation.

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