Numerical modelling of the improvements to primary and creep settlements offered by granular columns

Sexton, Brian G.; McCabe, Bryan A.

doi:10.1007/s11440-012-0205-4

Cited by 33 publications

(8 citation statements)

References 35 publications

(44 reference statements)

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“…Initial stresses were generated by K o procedure with the proposed value of lateral earth pressure, K = 1.0 for both column and soil reflecting wishin-place approach adopted in the model. This approach has also been adopted by many researchers [24][25][26]. Drained analysis was performed in this study where the embankment fill was assumed to be constructed slowly and there was no excess pore pressure generation in the model.…”

Section: Numerical Model and Analysismentioning

confidence: 99%

Stress Transfer Mechanism in 2D and 3D Unit Cell Models for Stone Column Improved Ground

Tan²

2014

Int. J. of Geosynth. and Ground Eng.

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Stone column has been used widely to improve the foundation for many structures. Many designs of stone column are based on the unit cell concept. However, the intrinsic mechanism of stress transfer between the column and the surrounding soil has not been investigated thoroughly. This paper presents the important features of stress sharing mechanism in unit cell concept under an embankment loading. The arching effect, the deformation mode, the stress concentration ratio and the plastic straining in the unit cell are the main focus of this paper. Finite element software PLAXIS was used to examine these features. Unit cell was simulated as a two-dimensional (2D) axisymmetrical model and a representative three dimensional model in the numerical analysis. Drained loading condition was analyzed in this study in which the embankment is assumed to be built slowly with no excess pore pressure buildup. The change of the stress concentration ratio as the embankment height increases was also studied. From this study, it was found that the bulging happened near the column head accompanied by multiple shear bands progressing along the column. Generally, stone column in the unit cell shared about 4-5 times more the loads than the surrounding soils throughout the column depth. In most cases, 2D and 3D models give results that are similar to each other especially on the settlement performance and the failure mechanism.

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Section: Numerical Model and Analysismentioning

confidence: 99%

Stress Transfer Mechanism in 2D and 3D Unit Cell Models for Stone Column Improved Ground

Tan²

2014

Int. J. of Geosynth. and Ground Eng.

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“…These parameters are largely based on data documented by Nash et al [38,39]. The validation of the SSC model for the Bothkennar test site has been documented elsewhere [44,45]. The predicted load-displacement behaviour of two pad footings is shown in Fig.…”

Section: Soft Clay Parameter Selectionmentioning

confidence: 99%

Numerical simulations of the reuse of piled raft foundations in clay

Sheil

2017

Acta Geotech.

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The development and growth of urban environments in recent years is requiring geotechnical engineers to consider foundation reuse as a more sustainable solution to inner city redevelopment. Two main phenomena associated with foundation reuse have been reported in the literature, namely 'preloading effects' and 'ageing effects'. The aim of this paper is to investigate the relative merits of these effects on the reusability of both piled and unpiled raft foundations in clay. Finite element analysis, in conjunction with an isotropic elasto-viscoplastic soil model, is employed for this purpose. The study is presented in two phases: (1) evaluation of preloading effects only by using a very low creep coefficient and (2) evaluation of combined preloading and creep effects. The variables considered in the parametric study include the number of piles, pile spacing, pile length, and soil type. Results show that both unpiled and piled rafts can exhibit significant capacity and stiffness increases upon reloading even for moderate levels of preload. Moreover, these increases are strongly dependent on the piled raft load sharing where unpiled raft and free-standing pile group capacity gains serve as upper and lower bounds, respectively, for that of a piled raft. This study underlines foundations reuse as an effective and sustainable solution for inner city redevelopment.

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“…Killeen and McCabe [16]). Sexton and McCabe [24] were among the first to use a model incorporating viscous effects with an application to stone columns.…”

Section: Introductionmentioning

confidence: 99%

Laboratory and numerical based analysis of floating sand columns in clayey soil

et al. 2019

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The inclusion of sand columns results in enhancing the bearing capacity of clayey soil, increase the rate of consolidation, presentation of liquefaction in loose sandy soils and provide lateral resistance against the horizontal movement. This research aims at investigating the effects of floating columns in clayey soil with silty deposits by developing small scale laboratory models. The effects of sand columns on soils of different shear strengths, slenderness ratio (L/D) of columns were investigated. Group effect was also investigated by varying spacing between the columns. Experimental results were compared with the numerical analysis results. A 15-noded triangular mesh was generated using a finite element tool PLAXIS 2D. Finite element analysis was performed using Mohr's Coulomb's criterion considering undrained analysis for soft clayey soil and drained analysis for sand columns. It was concluded that the sand columns can significantly increase the ultimate loading capacity of soft soils. Results show that critical length for floating column ranges from 4 to 5.5 times the diameter of the column, beyond which bulging occurs and loading capacity decreased. The effect of group was also investigated and observed that with high spacing between the sand columns, the group efficiency decreased. The axial capacity of sand columns decreases while increasing spacing between the columns.

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Numerical modelling of the improvements to primary and creep settlements offered by granular columns

Cited by 33 publications

References 35 publications

Stress Transfer Mechanism in 2D and 3D Unit Cell Models for Stone Column Improved Ground

Stress Transfer Mechanism in 2D and 3D Unit Cell Models for Stone Column Improved Ground

Numerical simulations of the reuse of piled raft foundations in clay

Laboratory and numerical based analysis of floating sand columns in clayey soil

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