Radial consolidation modelling incorporating the effect of a smear zone for a multilayer soil with downdrag caused by mandrel action

2010 ◽  
Vol 47 (9) ◽  
pp. 1024-1035 ◽  
Author(s):  
Cholachat Rujikiatkamjorn ◽  
Buddhima Indraratna
Keyword(s):  
Lower Layer ◽  
Soil Layer ◽  
Soil Consolidation ◽  
Soil Permeability ◽  
Soil System ◽  
Prefabricated Vertical Drains ◽  
Vertical Drains ◽  
Design Procedures ◽  
Surcharge Preloading ◽  
Time Required

A system of prefabricated vertical drains with surcharge preloading is an effective method for promoting radial drainage and accelerated soil consolidation. A piecewise technique is employed to analyse the radial consolidation in a multilayer soil system to include (i) the effect of soil downdrag and (ii) a smear zone having linearly varying soil permeability. The effect of soil dragged down from the upper soil layer into the lower layer has been analysed in terms of the time required for consolidation. It can be seen that the consolidation of the multilayer soil depends on smear zone characteristics, the permeability ratio between upper and lower soil layers, penetration depth, and drain spacing. Design procedures are described with the help of an example.

scholarly journals Ground settlement prediction of embankment treated with prefabricated vertical drains in soft soil

2018 ◽  
Vol 195 ◽  
pp. 03014
Author(s):  
Siswoko Adi Saputro ◽  
Agus Setyo Muntohar ◽  
Hung Jiun Liao
Keyword(s):  
Numerical Study ◽  
Soft Soil ◽  
Soil Permeability ◽  
K Value ◽  
Prefabricated Vertical Drains ◽  
Vertical Drains ◽  
Prefabricated Vertical Drain ◽  
Actual Settlement ◽  
Final Settlement ◽  
Best Fit

Excessive settlement due to consolidation can cause damage to the structure’s rest on soft soil. The settlement takes place in relatively longer. The preloading and prefabricated vertical drain (PVD) is often applied to accelerate the primary settlement. The issue in this research is the estimation of the settlement. The Asaoka method and the finite element method using PLAXIS-2D are used to estimate the final settlement of a PVD treated embankment. For the former, a complete record of the settlement was required; for the latter, some ground parameters are needed for the PLAXIS-2D analysis, such as the permeability of the soil. Because the installation process of PVD tends to influence the permeability of the in-situ soil around the PVD, the soil permeability after the installation of PVD needs to be adjusted. The numerical results were compared with actual settlement data to find out the best-fit input parameters (i.e. soil permeability) of the actual data. It was found that the best-fit soil permeability (k) used in the numerical study was about one-half of the k value determined from the laboratory test. The Root Mean Square Deviation shows that the settlement predicted by the numerical analysis has approximately 30% of the actual settlement.

scholarly journals An educational software for teaching soil consolidation

2017 ◽  
Author(s):  
Gonzalo García Ros ◽  
Manuel Cánovas Vidal ◽  
Juan Francisco Sánchez Pérez ◽  
Iván Alhama Manteca
Keyword(s):  
Educational Software ◽  
Low Cost ◽  
Surface Settlement ◽  
Excess Pore Pressure ◽  
Soil Consolidation ◽  
Depth Of Penetration ◽  
Consolidation Process ◽  
Prefabricated Vertical Drains ◽  
Vertical Drains ◽  
Graphical Environment

The educational tool SICOMED_3D has been created to simulate problems of soil consolidation by prefabricated vertical drains. Thanks to its nice interface of windows, the introduction of data is very fast and easy for the students, while providing users with simple handling and powerful calculations. Its graphical environment allows to get representations of the excess pore pressure, local settlements and total surface settlement. SICOMED_3D can also generate an animation that recreates the evolution of the surface settlement during the consolidation process. The software presents, like commercial softwares, the most common options (e.g., save and open cases files, save animations and representations, etc.). Although the program is created to be used in several fields, among others as an engineering or research tool, the main use of interest for this work is for educational purposes. Another important application is as low-cost laboratory practices, as students can experiment by modifying the soil properties, including the depth of penetration of the vertical drain, in a quick, simple and intuitive way.

scholarly journals Powerful Software to Simulate Soil Consolidation Problems with Prefabricated Vertical Drains

Water ◽  
2018 ◽  
Vol 10 (3) ◽  
pp. 242 ◽  
Author(s):  
Gonzalo García-Ros ◽  
Iván Alhama ◽  
Manuel Cánovas
Keyword(s):  
Soil Consolidation ◽  
Prefabricated Vertical Drains ◽  
Vertical Drains

scholarly journals Compression and consolidation behaviors of lime-treated dredging slurry under vacuum pressure

2021 ◽  
Author(s):  
Xueyu Geng
Keyword(s):  
Mechanical Characteristics ◽  
Vacuum Pressure ◽  
Laboratory Model ◽  
Log P ◽  
Soil Permeability ◽  
Lime Treatment ◽  
Vacuum Preloading ◽  
Prefabricated Vertical Drains ◽  
Vertical Drains ◽  
Oedometer Tests

Dredging slurry is treated by a combination of lime treatment and vacuum preloading. However, the mechanical characteristics and consolidation mechanics of lime-treated slurry under vacuum loading is not fully understood, making it difficult to predict slurry settlement. In this study, we develop a laboratory model of lime-treated slurry and subject it to vacuum preloading to investigate the compression and consolidation behaviors. The results demonstrate the reduction of the risk of clogging around the prefabricated vertical drains, the increase in soil permeability, and the improvement of vacuum preloading upon lime treatment. log (1 + e)-log p curves for soils with different percentages of lime content are obtained through a series of modified oedometer tests. Based on these curves, an analytical solution for lime-treated slurry settlement under vacuum preloading was derived and validated through laboratory tests. The solution can be used to predict lime-treated slurry settlement under vacuum pressure effectively.

scholarly journals Design procedure for vertical drains considering a linear variation of lateral permeability within the smear zone

2009 ◽  
Vol 46 (3) ◽  
pp. 270-280 ◽  
Author(s):  
Cholachat Rujikiatkamjorn ◽  
Buddhima Indraratna
Keyword(s):  
Shear Strength ◽  
Design Procedure ◽  
Undrained Shear Strength ◽  
Soil Consolidation ◽  
Linear Variation ◽  
Vertical Drains ◽  
Multi Stage ◽  
Surcharge Preloading ◽  
Zone Ii ◽  
Undrained Shear

A system of vertical drains with surcharge preloading is an effective method for promoting radial drainage and accelerated soil consolidation. This study presents a procedure for the design of vertical drains that significantly extends the previous technique proposed by the authors to include: (i) a linear reduction of lateral permeability in the smear zone, (ii) the effect of overlapping smear zones in a closely spaced drain network, and (iii) the gain in undrained shear strength due to consolidation. Design examples are provided for both single stage and multi-stage embankment construction demonstrating the convenient use of the proposed solutions in practical situations.

scholarly journals Analytical solutions and design curves for vacuum-assisted consolidation with both vertical and horizontal drainage

2007 ◽  
Vol 44 (2) ◽  
pp. 188-200 ◽  
Author(s):  
Cholachat Rujikiatkamjorn ◽  
Buddhima Indraratna
Keyword(s):  
Analytical Modeling ◽  
Excess Pore Pressure ◽  
Soil Consolidation ◽  
Factor Analyses ◽  
Soil Permeability ◽  
Vacuum Preloading ◽  
Vertical Drains ◽  
Design Charts ◽  
Horizontal Drainage ◽  
Degree Of Consolidation

A system of vertical drains combined with vacuum preloading is an effective method for promoting radial flow to accelerate soil consolidation. This study presents the analytical modeling of the consolidation of vertical drains incorporating vacuum preloading considering both vertical and horizontal drainage. The effects of a number of dimensionless parameters involving the drain length, soil permeability, and vacuum pressure are examined through average excess pore pressure, degree of consolidation, associated settlement, and time factor analyses. An analysis of selected case histories compliments the use of the proposed solutions. Design charts are also presented for practical use.Key words: analytical solution, consolidation, design charts, vertical drains.

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