Case Study: Ground Improvement of Yangtze River Floodplain Soils with Combined Vacuum and Surcharge Preloading Method

2019 ◽  
Vol 19 (12) ◽  
pp. 05019008
Author(s):  
Jianwen Ding ◽  
Xing Wan ◽  
Chongqi Zhang ◽  
Zhijiang He ◽  
Lun Zhao
Keyword(s):  
Yangtze River ◽  
Ground Improvement ◽  
River Floodplain ◽  
Floodplain Soils ◽  
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.

scholarly journals A case study of vacuum tube-well dewatering technology for improving deep soft soil in Yangtze River floodplain

2021 ◽  
Vol 80 (17) ◽  
Author(s):  
Biao Zeng ◽  
Yu Zhen ◽  
Dingwen Zhang ◽  
Tao Meng ◽  
Zejia Gong ◽  
...  
Keyword(s):  
Yangtze River ◽  
Soft Soil ◽  
Vacuum Tube ◽  
River Floodplain ◽  
Tube Well ◽  
Deep Soft Soil

scholarly journals A Case Study of Vacuum Tube-Well Dewatering Technology for Improving Deep Soft Soil in Yangtze River Floodplain

2021 ◽  
Author(s):  
Biao Zeng ◽  
Yu Zhen ◽  
Dingwen Zhang ◽  
Tao Meng ◽  
Zejia Gong ◽  
...  
Keyword(s):  
Yangtze River ◽  
Water Pressure ◽  
Ground Improvement ◽  
Soft Soil ◽  
Test Site ◽  
Engineering Properties ◽  
Vacuum Tube ◽  
River Floodplain ◽  
Tube Well ◽  
Deep Soft Soil

Abstract Deep soft soil of the Yangtze River floodplain in Nanjing has a special interlayer structure, which provides favorable conditions for the application of vacuum tube-well dewatering technology. This paper focuses on the design, construction and treatment effect of vacuum tube-well dewatering technology. The hydrological parameters and the hydraulic connections between the various layers of the site have been ascertained through two simple single-well multi-holes pumping tests. Moreover, the layout of vacuum tube-wells and depressurization wells in a test site with 84m length and 84m width was designed based on the above parameters. Field tests of vacuum tube-well dewatering technology were conducted on the test site. And the changes of groundwater level, ground settlement and pore water pressure during the test was monitored. The CPTU test technology was used to quickly evaluate the engineering properties of the site before and after treatment. Finally, combined with the settlement monitoring data, the hyperbolic method was used to predict the final settlement. The results indicated that consolidation efficiency of vacuum tube-well dewatering technology has obvious advantages. Implications of this study can provide a reference for the construction design of the site's ground improvement consolidation and other similar projects.

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