Numerical analysis of unconnected piled raft with cushion

Ata, Alaa; Badrawi, Essam Farouk; Nabil, Marwa

doi:10.1016/j.asej.2014.11.002

Cited by 40 publications

(12 citation statements)

References 10 publications

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“…However, there is limitation of computational results owing to the commonly applied way of contact formulation in ABAQUS software through the zero-thickness algorithm, the use of reduced-integration to take advantage of computational cost, and employing Mohr-Coulomb constitutive relationship to approximately capture the nonlinear soil behaviour. Despite these Advances in Civil Engineering limitations, robust predictions can still be made in numerical studies adopting the Mohr-Coulomb criteria and the reduced-integration formulation [9,45,46].…”

Section: Verification Of the Finite-element Modelmentioning

confidence: 99%

“…e CFG piles crowned with a cushion layer receive the foundation load indirectly; and owing to the deformability characteristics of the cushion, piles' head pricks into the mattress layer, leading to relative pile/soil settlement that provokes negative side friction (NSF) to develop on the upper 15-50% of the pile length [3][4][5][6][7]. In this regard, researchers such as Halder and Manna [3], Rui et al [4], and Fioravante and Giretti [8] conducted centrifuge and static geotechnical model tests, and Tradigo et al [6] and Ata et al [9] performed numerical analyses while Jiang and Liu [5] and Wu et al [7] established differential equation based on typical unit calculation model to deduce the calculation formula of the depth of neutral plane and pile-soil stress ratio.…”

Section: Introductionmentioning

confidence: 99%

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Numerical Analysis on the Load Sharing Performance of Long‐Short CFG Pile Composite Foundation Subjected to Rotation of Adjacent Retaining Wall

Uge

Guo

Liu

2021

Advances in Civil Engineering

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The stress and displacement boundary conditions of excavation retaining structures affect the deformation mechanism and movement of the retained soil mass. The soil movement disturbs the load sharing performance and structural integrity of cement-fly ash-gravel (CFG) pile composite foundations existing in the vicinity, which merits considerable research work. This article presents results from 3D finite element analyses performed to study the influence of retaining wall rotation on the load sharing characteristics of adjacent CFG pile composite foundation comprising long and short piles. To verify the numerical model, a relatively large-scale 1 g physical model test was conducted. It is revealed that to arrive at a new static equilibrium during progression of wall rotation, the percentage load sharing ratios of the long and short piles change increasingly while the load proportion carried by the upper soil reduces remarkably. The percentage load sharing characteristics of CFG pile composite foundation are more affected in immediate proximity to the wall than those located at far distance. For the foundation having 3 × 3 long and short piles placed at 3.0–15.0 m away from the wall, the location resulted in a reduction of soil bearing capacity ranging between 1.4 and 7.5% of the total imposed load while the corresponding increase in the % load borne by the long and short pile range was 0.83–4.15 and 0.59–3.36%, respectively. For the other parameters considered in this article viz. pile spacing, subsoil stiffness, cushion stiffness and thickness, and applied working load, the increment in % load sharing of the long and short pile range was 3.45–4.15, 1.3–5.79, 1.48–3.36, 4.15–4.79, and 3.67–4.15% and 3.36–4.67, 1.43–4.99, 1.48–3.36, 3.36–3.64, and 1.38–3.36% of the imposed load, respectively. Moreover, the long piles’ load sharing proportion was higher than that of short piles, and peripheral piles received larger load proportion.

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Section: Verification Of the Finite-element Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Numerical Analysis on the Load Sharing Performance of Long‐Short CFG Pile Composite Foundation Subjected to Rotation of Adjacent Retaining Wall

Uge

Guo

Liu

2021

Advances in Civil Engineering

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“…In the finite element analysis of the pile-raft foundation, a solid element is used to simulate the pile, and the pile-soil interaction is, thus, considered by setting the interface elements [16][17][18]22]. The common interface model is the zero-thickness interface model proposed by Goodman et al [29].…”

Section: Solid Element and Interfacementioning

confidence: 99%

“…Schweiger et al [24], Tradigo et al [25], and Engin et al [30] verified the performance of single-pile foundations, pile group foundations, and pile-raft foundations simulated using the embedded pile element instead of the solid pile element. In the finite element analysis of the pile-raft foundation, a solid element is used to simulate the pile, and the pile-soil interaction is, thus, considered by setting the interface elements [16][17][18]22]. The common interface model is the zero-thickness interface model proposed by Goodman et al [29].…”

Section: Embedded Pile Elementmentioning

confidence: 99%

“…For this complex structural system, the finite element method (FEM) is an effective analytical tool. Liang et al [16], Zheng et al [17], Sharma et al [18], Tradigo et al [19], Rasouli et al [20], Ata et al [21], and Ata et al [22] studied the load-transfer mechanism and settlement characteristics of piled rafts with cushions using three-dimensional (3D) finite element analysis. It was assumed in these studies that the pile was in homogeneous soil, and a solid element was used to simulate the pile.…”

Section: Introductionmentioning

confidence: 99%

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3D Numerical Analysis of Synergetic Interaction between High-Rise Building Basement and CFG Piles Foundation

et al. 2018

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A strong bearing capacity and the satisfaction of strict settlement requirements are necessary for high-rise buildings. A single-raft foundation cannot meet certain settlement requirements, in which case CFG (cement/fly ash/gravel, an emerging and sustainable construction material) piles can be used in the foundation to set up a cushion between the top of the pile and the raft slab, where the piles act as settlement reducers. The rafts of disconnected piles (DPs) exhibit complex synergetic interactions involving the raft, cushion, pile, and soil under the load of the superstructure. Multiple piles in particular lead to an increase in the number of degrees of freedom of the problem, resulting in difficulty in solving it. However, when the number of piles is very large and the structure is complex-for example, many buildings are placed on the same raft with basement structures-even if the embedded pile element is used during numerical calculations, either the method remains prone to non-convergence or the time needed for numerical calculations is too long. It is, thus, difficult to satisfy the requirement of an efficient scheme of evaluation in practice. To solve this problem, a method that uses a simulation of the integral equivalent of the CFG pile reinforcement zone is proposed in this paper. In the CFG pile reinforcement zone, the effect of the pile is reflected in the enhancement of parameters of the soil in the strengthened zone, and the reinforcement zone (including the soil and the pile) is regarded as an anisotropic elastoplastic material. As the structure of the pile is no longer needed in the model, its elimination significantly reduces the complexity of the model and improves its calculation efficiency. An example of a numerical calculation is provided to verify the viability and accuracy of the integral equivalent simulation method in comparison with the embedded pile element simulation method. Finally, the proposed method is applied to the three-dimensional numerical analysis of a scheme for the treatment of foundations of high-and low-rise buildings with basements, and its effectiveness is further verified through comparison with theoretical results.

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Model Study of Piled Raft Foundation

Alimunnisa

Arora

2019

Lecture Notes in Civil Engineering

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Numerical analysis of unconnected piled raft with cushion

Cited by 40 publications

References 10 publications

Numerical Analysis on the Load Sharing Performance of Long‐Short CFG Pile Composite Foundation Subjected to Rotation of Adjacent Retaining Wall

Numerical Analysis on the Load Sharing Performance of Long‐Short CFG Pile Composite Foundation Subjected to Rotation of Adjacent Retaining Wall

3D Numerical Analysis of Synergetic Interaction between High-Rise Building Basement and CFG Piles Foundation

Model Study of Piled Raft Foundation

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