Numerical analysis for shaft stress in different parts of CFG pile

The problem of disposing the soft soil foundation will appear inevitably during the construction of modem high way. There are many ways to dispose the soft foundation. One of those is CFG pile technology. Take the CFG pile technology in the GuangWu Expressway for example, the influence factors of embankment settlement were discussed in detai by numerical analysis, some useful conclusions are obtained from the computational results.

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

Applied Sciences ◽

10.3390/app8112040 ◽

2018 ◽

Vol 8 (11) ◽

pp. 2040 ◽

Cited By ~ 3

Author(s):

Xirong Niu ◽

Yangping Yao ◽

Yanfang Sun ◽

Yuhao He ◽

Haiqing Zhang

Keyword(s):

Numerical Analysis ◽

Degrees Of Freedom ◽

Construction Material ◽

Three Dimensional ◽

Simulation Method ◽

Numerical Calculations ◽

Sustainable Construction ◽

Elastoplastic Material ◽

High Rise ◽

Cfg Pile

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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