Settlement calculation for long-short composite piled raft foundation

Zhao, Minghua; Zhang, Ling; Yang, Minghui

doi:10.1007/s11771-006-0026-4

Cited by 20 publications

(12 citation statements)

References 4 publications

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“…Although the stress correction method is relatively simple, it is difficult to determine the pile-soil stress ratio and the stress correction coefficient of the composite foundation, and the role of long and short piles is ignored during the calculation process. According to the shear displacement method, Zhao et al [12,13] introduced a pile-pile and pile-soil interaction model based on specific assumptions. With the effect of the bedding layer considered, a method to calculate the settlement of a composite foundation was proposed based on the bedding-pile-soil joint action, but it did not take into account relevant problems caused by loess collapsibility.…”

Section: Calculation Of Settlement Of Composite Pile Foundation With Long and Short Piles In Loess Areasmentioning

confidence: 99%

“…In terms of calculating the settlement deformation of long and short piles, Yang et al [11] proposed a practical settlement calculation method for composite pile foundations with long and short piles and applied it to the analysis of the settlement of a high-rise residential building. Zhao et al [12,13] established a calculation model for the settlement of composite pile foundations with long and short piles based on the shear displacement method with certain simplifying assumptions. Hong Y et al [14] carried out a field study on the downdrag and dragload of two pairs of bored piles installed in consolidating ground.…”

Section: Introductionmentioning

confidence: 99%

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Calculation of Bearing Capacity and Deformation of Composite Pile Foundation with Long and Short Piles in Loess Areas

Yan-peng

Yang

2020

Advances in Civil Engineering

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In order to calculate the bearing capacity and settlement deformation of composite pile foundations with long and short piles in collapsible loess areas, the theoretical approximate solution was used to obtain the location of the neutral point of single piles. Additionally, based on the equation to calculate the bearing capacity of multielement composite foundations, a method considering the negative frictional resistance was proposed for calculating the bearing capacity of composite pile foundations with long and short piles. Based on the shear displacement method and the principle of deformation control, an equation to calculate the displacement and deformation of a composite pile foundation was presented. A model test with different operating conditions, i.e., a single pile, four piles, and eight piles, was designed to verify the proposed calculation methods. The results show that the location of the neutral point has a significant influence on the single-pile negative frictional resistance, and the neutral point ratio of the calculation meets the value range of the practical project. When the load at the top of the pile is relatively small, the experimental curve is consistent with the theoretical calculation curve, whereas when the load is comparatively large, the theoretically calculated displacement increase at the top of the pile is greater than the measured one. Under the premise that the theoretical calculation is in good agreement with the results, the theoretical value is larger than the actual value. And it contributes to strengthening engineering safety.

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Section: Calculation Of Settlement Of Composite Pile Foundation With Long and Short Piles In Loess Areasmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Calculation of Bearing Capacity and Deformation of Composite Pile Foundation with Long and Short Piles in Loess Areas

Yan-peng

Yang

2020

Advances in Civil Engineering

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“…Studies showed that reinforcing the shallow soft soil with stone columns can effectively improve the bearing interaction of the raft. Zhao et al [21] discussed the mechanism of the long-short composite pile-raft foundation. Considering the influence of the cushion, the flexibility factors of the interaction were determined and a settlement calculation method for the long-short composite pile-raft foundation was proposed.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Deformation Characteristics of Long‐Short Pile Composite Foundation in Salt Lake Area, Iran

Liu¹,

Yang

Zhang

et al. 2019

Advances in Civil Engineering

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To study the settlement and deformation characteristics of a long-short pile composite foundation and its influencing factors, the indoor centrifuge model test and numerical simulations were performed under the actual working conditions to treat the saline soft soil foundation in the Soltan salt lake area of Iran. Firstly, the settlement of a long-short pile composite foundation and the law of pile-soil stress ratio development with time were studied using a centrifuge model test. In addition, FLAC3D was used to simulate the test conditions, and it has been observed that the numerical and experimental results were in good agreement. Based on the numerical model, the effects of the replacement rate of long and short piles, cushion modulus, and pile length on the settlement of the composite foundation and the stress ratio of long and short piles were analyzed. The results show that the long-short pile composite foundation can effectively control settlement. Compared to the untreated foundation, the total settlement of a long-short pile composite foundation was reduced by 67%, and the postconstruction settlement was reduced by 47.7%. Compared to the final settlement of the composite foundation obtained using the centrifuge model test, the error range of the numerical simulation results was between 2.4% and 8%. The influence of pile spacing on the settlement and stress characteristics of a long-short pile composite foundation is greater than that attributable to the arrangement of the piles. Under this geological condition, it is reasonable to choose a pile spacing of 4d∼5d. When the long pile reaches the bearing stratum, the length of the short pile should not exceed 0.6 times the length of the long pile. The setting cushion not only reduces uneven settlement of the composite foundation but also improves the joint bearing capacity of the pile and the soil between the piles.

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“…Liang et al [7] proposed a simplified analytical model for the optimal selection of cushion stiffness. Zhao et al [26] developed a settlement calculation method for a long-short pile composite pile-raft foundation. Zhang and Shi [27] constructed a mechanical model of a pile-piercing cushion and a method to calculate pile-soil interaction.…”

Section: Introductionmentioning

confidence: 99%

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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Settlement calculation for long-short composite piled raft foundation

Cited by 20 publications

References 4 publications

Calculation of Bearing Capacity and Deformation of Composite Pile Foundation with Long and Short Piles in Loess Areas

Calculation of Bearing Capacity and Deformation of Composite Pile Foundation with Long and Short Piles in Loess Areas

Analysis of Deformation Characteristics of Long‐Short Pile Composite Foundation in Salt Lake Area, Iran

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

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