Two Case Histories of Vertical Drains in Very Soft Clays

2015 ◽  
pp. 151-164
Author(s):  
Marcio Souza Soares de Almeida ◽  
Maria Esther Soares Marques ◽  
Alexandre Pereira Spotti
Keyword(s):  
Case Histories ◽  
Vertical Drains ◽  
Soft Clays

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.

Radial consolidation with vertical drains and general time-dependent loading

2009 ◽  
Vol 46 (1) ◽  
pp. 25-36 ◽  
Author(s):  
Enrico Conte ◽  
Antonello Troncone
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Time Dependent ◽  
Case Histories ◽  
Vertical Drains ◽  
Excess Pore Water Pressure ◽  
Theoretical Methods ◽  
Consolidation Settlement ◽  
Degree Of Consolidation ◽  
General Time

A simple-to-use analytical solution for radial consolidation with vertical drains under equal strain conditions is presented in this paper. This solution accounts for the effects of soil smear, drain hydraulic resistance, and general time-dependent loading. A number of comparisons with other theoretical methods are shown to assess the accuracy of the proposed solution, both in terms of excess pore-water pressure and degree of consolidation settlement. Moreover, two case histories documented in the literature are analysed to evaluate the main parameters affecting radial consolidation in the presence of vertical drains.

Modelling the effect of vertical drains in two-dimensional finite element analyses of embankments on soft ground

1995 ◽  
Vol 32 (5) ◽  
pp. 795-807 ◽  
Author(s):  
C.C. Hird ◽  
I.C. Pyrah ◽  
D. Russell ◽  
F. Cinicioglu
Keyword(s):  
Finite Element ◽  
Plane Strain ◽  
Unit Cell ◽  
Lateral Strain ◽  
Soft Ground ◽  
Two Dimensional ◽  
Finite Element Analyses ◽  
Case Histories ◽  
Vertical Drains ◽  
Dimensional Finite Element

A recently developed method for modelling the effect of vertical drains in plane strain finite element analyses of consolidation beneath embankments on soft ground is applied to three case histories. Analyses are reported for the consolidation of the soil served by a single drain (a unit cell) under conditions of no lateral strain. In all three cases a good match was obtained between the average degrees of consolidation in an axisymmetric unit cell and the equivalent plane strain unit cell. This suggests that the method could be used to facilitate full two-dimensional analyses of many embankments. The results of the analyses are also compared with the available field data. Key words : vertical drains, consolidation, finite elements, embankments.

scholarly journals Preloading system with partially penetrating vertical drains in marine soft clays in Egypt: 2D and 3D comparative FE study

2021 ◽  
Vol 13 (3) ◽  
pp. 10-22
Author(s):  
Ahmed M. Abouhashem ◽  
Alaa El-Din A. El-Gendy ◽  
Mohamed H. Rabie ◽  
Mohamed A. Mostafa
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Vertical Displacement ◽  
Design Parameters ◽  
Marine Clay ◽  
Prefabricated Vertical Drains ◽  
Vertical Drains ◽  
Soft Clays ◽  
Clay Deposits ◽  
Three Dimensional Finite Element

A large-scale trial embankment provided with partially penetrating prefabricated vertical drains (PVD) was installed in consolidating marine clay deposits at East-Port said industrial zone project in Egypt. The trial embankment was constructed with a bottom area of 150x150m and a height of 5.5m to evaluate the efficiency of the improvement system and verify the design parameters. An intensive instrumentation system was built-up including shallow settlement indicators, vibrating wire piezometers, extensometer, and inclinometers. Two and three-dimensional finite element analyses (FE) were performed to study the effect of the preloading system provided with partially PVD in consolidating marine clay deposits. FE models were validated and showed good agreement with the field observations in terms of vertical displacement of embankment center, and lateral soil deformation beneath the embankment toe.

Electroosmosis-enhanced preloading consolidation via vertical drains

1998 ◽  
Vol 35 (3) ◽  
pp. 491-499 ◽  
Author(s):  
J Q Shang
Keyword(s):  
Electric Field Intensity ◽  
Treatment Time ◽  
Spatial Configuration ◽  
Soil Improvement ◽  
Excess Pore Pressure ◽  
Vertical Drains ◽  
Soft Clays ◽  
Surcharge Preloading ◽  
Surcharge Load ◽  
Degree Of Consolidation

An analytical model of electroosmosis-enhanced preloading consolidation via vertical drains is developed for the design of the combined preloading and electroosmotic consolidation of clay soils. The excess pore pressure and average degree of consolidation are computed and examined for the effects of surcharge load, electric field intensity, treatment time, spatial configuration of electrodes, drainage path, and soil properties. The model is evaluated using the results of a well-known electroosmotic consolidation field test reported in the literature.Key words: consolidation, electroosmosis, surcharge preloading, vertical drains, soil improvement, soft clays.

The bearing capacity of dykes and fills founded on soft soils of limited thickness

1983 ◽  
Vol 20 (3) ◽  
pp. 428-436 ◽  
Author(s):  
V. Silvestri
Keyword(s):  
Stability Analysis ◽  
Slope Stability ◽  
Bearing Capacity ◽  
Theoretical Approach ◽  
Soft Clay ◽  
Case Histories ◽  
Soft Clays ◽  
The Stability ◽  
Clay Layers ◽  
Limited Depth

This paper analyzes the stability of dykes and fills founded on soft clay layers of limited depth and is divided into two sections.In the first section, the critical condition at which failure is impending is analyzed in terms of the bearing capacity in the soft clay foundation, instead of the conventional slope stability approach of the fill–clay foundation interaction. The theoretical approach is based upon the works of Jurgenson, Hill, Meyerhof, Mandel, and Salençon. The solutions obtained by these investigators are of considerable interest and may be easily applied to geotechnical engineering problems.In the second section, several case histories dealing with failures of fills on soft clays will be presented and analyzed by means of the present approach. It will be shown that the plasticity approach, when compared with the conventional slope stability analysis, is much easier to apply and is able to represent adequately the failure criterion of fills founded on layers of soft clays of limited depth. Keywords: bearing capacity, soft clays, plasticity, fills, limited thickness.

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