Numerical assessment of equivalent diameter equations for prefabricated vertical drains

2012 ◽  
Vol 49 (12) ◽  
pp. 1427-1433 ◽  
Author(s):  
Hossam M. Abuel-Naga ◽  
Abdelmalek Bouazza ◽  
Dennes T. Bergado
Keyword(s):  
Equivalent Diameter ◽  
Prefabricated Vertical Drains ◽  
Vertical Drains ◽  
Numerical Assessment

Discussion of “Numerical assessment of equivalent diameter equations for prefabricated vertical drains”

2013 ◽  
Vol 50 (7) ◽  
pp. 801-804
Author(s):  
Hui Wu ◽  
Liming Hu
Keyword(s):  
Numerical Model ◽  
Three Dimensional ◽  
Equivalent Diameter ◽  
Prefabricated Vertical Drains ◽  
Vertical Drains ◽  
Numerical Assessment ◽  
Equivalent Equation ◽  
3D Numerical Model ◽  
The Difference ◽  
2D Numerical Model

The Discussion revises the figure that compares different equivalent-diameter equations for prefabricated vertical drains, and the result of another equivalent equation that has been widely used in practice is also added into the figure. In addition, a three-dimensional (3D) numerical model is developed to compare with the two-dimensional (2D) numerical model used in the paper. The result indicates that the difference between the 3D and 2D models can be about 5%.

Characteristics and Performance of Prefabricated Vertical Drains for Enhanced Soil Flushing

1997 ◽  
Vol 1596 (1) ◽  
pp. 93-100 ◽  
Author(s):  
J. D. Quaranta ◽  
M. A. Gabr ◽  
D. Szabo ◽  
J. J. Bowders
Keyword(s):  
Pilot Scale ◽  
Equivalent Diameter ◽  
Embedment Depth ◽  
Areal Extent ◽  
Prefabricated Vertical Drains ◽  
Vertical Drains ◽  
Soil Flushing ◽  
Tracer Testing ◽  
Zone Of Influence ◽  
And Performance

The use of prefabricated vertical drains (PVDs) under vacuum conditions for soil flushing was investigated with soils consisting of 100 percent sand or a combination of 80 percent sand and 20 percent kaolinite. Tests of the 100 percent sand specimens indicated that the areal extent of the PVD zone of influence remained approximately 16 to 21 times the PVD-equivalent diameter (PVD circumference/π) as the extraction vacuum increased from 2.5 to 20 kPa. Tests of the sand kaolinite specimens (80/20 soil) indicated that the areal extent of the PVD zone of influence remained approximately 5 to 8 times the PVD equivalent diameter as the extraction vacuum increased from 2.5 to 20 kPa. The effective zone of influence in the 80/20 soil did not show a corresponding increase in areal extent as the vacuum pressure was increased beyond the PVD embedment depth. Pilot-scale tracer flushing tests demonstrated the feasibility of using PVDs for flushing 100 percent sand soil. The tracer testing demonstrated that longer flushing times were necessary to achieve 80 percent cleanup levels as the dry unit weights of soil increased from 1.57 to 1.67 g/cm3. The ratio of final to initial concentration reached 0.2 after flushing of the 1.57 g/cm3 soil for approximately 40 minutes. A similar ratio was reached after flushing of the 1.67 g/cm3 soil for 50 minutes.

scholarly journals Numerical Investigation to the Effect of Suction-Induced Seepage on the Settlement in the Underwater Vacuum Preloading with Prefabricated Vertical Drains

2021 ◽  
Vol 9 (8) ◽  
pp. 797
Author(s):  
Shu Lin ◽  
Dengfeng Fu ◽  
Zefeng Zhou ◽  
Yue Yan ◽  
Shuwang Yan
Keyword(s):  
Practical Implication ◽  
Soil Surface ◽  
Small Strain ◽  
Seepage Flow ◽  
Excess Pore Pressure ◽  
Combined Effects ◽  
Vacuum Preloading ◽  
Prefabricated Vertical Drains ◽  
Vertical Drains ◽  
The Difference

Vacuum preloading combined with prefabricated vertical drains (PVDs) has the potential to improve the soft sediments under water, however, its development is partly limited by the unclear understanding of the mechanism. This paper aims to extend the comprehension of the influential mechanism of overlapping water in the scenario of underwater vacuum preloading with PVDs. The systematic investigations were conducted by small strain finite element drained analyses, with the separated analysis schemes considering suction-induced consolidation, seepage and their combination. The development of settlement in the improved soil region and the evolution of seepage flow from the overlapping water through the non-improved soil region into improved zone are examined in terms of the build-up of excess pore pressure. Based on the results of numerical analyses, a theoretical approach was set out. It was capable to estimate the time-dependent non-uniform settlement along the improved soil surface in response to the combined effects of suction-induced consolidation and seepage. The difference of underwater and onshore vacuum preloading with PVDs is discussed with some practical implication and suggestion provided.

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