Three-dimensional analysis of embankments on soft soils incorporating vertical drains by finite element method

Borges, José Leitão

doi:10.1016/j.compgeo.2004.11.001

Cited by 53 publications

(23 citation statements)

References 12 publications

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“…The accuracy of the finite element program has been assessed in several ground structures involving consolidation (Borges 1995(Borges , 2004Borges andCardoso 2001, 2002;Costa 2005;Domingues 2006) by comparing numerical results to field measurements. For instance, with regard to embankments on soft ground, Borges (1995) compared results of two geosynthetic-reinforced embankments, one constructed up to failure (Quaresma 1992) and the other observed until the end of consolidation (Yeo 1986;Basset 1986a, b).…”

Section: Finite Element Programmentioning

confidence: 99%

Cut Slopes in Clayey Soils: Consolidation and Overall Stability by Finite Element Method

Borges

2008

Geotech Geol Eng

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When a cut slope in a saturated clay is undertaken, a transient water flow occurs and stress transferences from the water to the soil skeleton take place in time (consolidation). Mainly in strongly overconsolidated clays, these stress transferences may determine swelling of soil and therefore reduction of its shear strength in time. However, the lowering of the water level associated to the cut increases effective mean stress, which may therefore counterbalance the above-mentioned effect. In the paper, the behaviour of a cut slope in an overconsolidated clay is analysed by a finite element program that incorporates the Biot consolidation theory (coupled analysis), with constitutive relations simulated by the p-q-h critical state model. In addition, the variation in time of the overall stability is assessed with a computer program that uses the finite element results and formulations of the critical state soil mechanics. In order to achieve a more complex geotechnical interpretation of the problem, the analysis in time of the excess pore pressures, effective stresses, displacements and stress levels is also presented. Finally, comparisons of stability results are analysed by changing some parameters, namely the problem geometry (weight of excavated soil) and the over-consolidation ratio of the clay.

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Section: Finite Element Programmentioning

confidence: 99%

Cut Slopes in Clayey Soils: Consolidation and Overall Stability by Finite Element Method

Borges

2008

Geotech Geol Eng

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“…Since the last decade, improved and user-friendly three-dimensional finite element (3D) codes have emerged as a powerful tool capable of capturing ground response details that cannot be analysed using traditional 2D (plane strain) finite element software (Small and Zhang, 1991). For 3D analysis, a single row of drains with influence zones has been considered, but without considering a smear zone (Cheung et al 1991;Borges, 2004). This study demonstrates that a 3D analysis should be considered for embankments where the 2D plane strain condition may not be appropriate due to the nature of embankment geometry among the other reasons.…”

Section: Introductionmentioning

confidence: 99%

2D and 3D Numerical Modeling of Combined Surcharge and Vacuum Preloading with Vertical Drains

2008

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Abstract:This paper presents a three-dimensional (3D) and two-dimensional (2D) numerical analysis of a case study of a combined vacuum and surcharge preloading project for a storage yard at Tianjin Port, China. At this site, a vacuum pressure of 80 kPa and a fill surcharge of 50 kPa was applied on top of the 20m thick soft soil layer through prefabricated vertical drains (PVD) to achieve the desired settlements and to avoid embankment instability. In 3D analysis, the actual shape of PVDs and their installation pattern with the in-situ soil parameters were simulated. In contrast, the validity of 2D-plane strain analysis using equivalent permeability and transformed unit cell geometry was examined. In both cases, the vacuum pressure along the drain length was assumed to be constant as substantiated by the field observations. The finite element code, ABAQUS, using the modified Cam-clay model was used in the numerical analysis. The predictions of settlement, pore water pressure and lateral displacement were compared with the available field data, and an acceptable agreement was achieved for both 2D and 3D numerical analyses. It is found that both 3D and equivalent 2D analyses give similar consolidation responses at the vertical cross section where the lateral strain along the longitudinal axis is zero. The influence of vacuum may extend more than 10m from the embankment toe, where the lateral movement should be monitored carefully during the consolidation period to avoid any damage to adjacent structures.

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“…However, the discrepancy between the measured and predicted consolidation based on the approximate 2D modelling techniques can be found from previous studies (Hird et al 1992). Borges (2004) described the advantages of 3D FEM for vertical drains.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Radial Vacuum-Assisted Consolidation Using 3D Finite Element Method

Rujikiatkamjorn

Indraratna

2007

Advances in Measurement and Modeling of Soil Behavior

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In this study, a 3D numerical modelling of a single vertical drains consolidation incorporating vacuum preloading considering both vertical and horizontal drainage is presented. The effects of nonlinear soil compressibility, varying permeability and vacuum pressure distribution along the drain are examined through the dissipation of average excess pore pressure and associated settlement. A selected case history, using 3D finite element method, is employed to analyse two embankments constructed at the Second Bangkok International Airport, Thailand stabilised with prefabricated vertical drains and vacuum preloading. The behaviour of this embankment including settlements and excess pore pressures is then compared with the numerical predictions. This study reveals a close agreement between the predictions results obtained from the numerical model and the field measurements.

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Three-dimensional analysis of embankments on soft soils incorporating vertical drains by finite element method

Cited by 53 publications

References 12 publications

Cut Slopes in Clayey Soils: Consolidation and Overall Stability by Finite Element Method

Cut Slopes in Clayey Soils: Consolidation and Overall Stability by Finite Element Method

2D and 3D Numerical Modeling of Combined Surcharge and Vacuum Preloading with Vertical Drains

Analysis of Radial Vacuum-Assisted Consolidation Using 3D Finite Element Method

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