Effect of Size on the Stability of Narrow Foundation Pits

He, Caihao; Lu, Yi; Yang, Yanlu

doi:10.1155/2022/7391622

Cited by 3 publications

(2 citation statements)

References 9 publications

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“…The deformation curve is bow-shaped, with smaller values at both ends and larger values in the middle, and the lateral displacement of the wall increases as the excavation depth increases. Moreover, the position of the maximum horizontal wall displacement moves progressively downwards, which is consistent with the typical lateral deformation pattern of embedded rock walls [16].…”

Section: Validation Of the Modelsupporting

confidence: 82%

Deformation Characteristics and Control Methods of Deep Foundation Pit Excavation in Watery Sandy Soil Area

Liu,

Zhan,

Zheng

et al. 2023

Advances in Frontier Research on Engineering Structures

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This paper investigates the deformation characteristics and control methods of support structures during deep foundation pit excavation, using the foundation pit at the Diejiao Station of Foshan Metro Line 3 as a case study. A 3D nonlinear finite element software is employed for excavation simulation, adopting coupled pore fluid diffusion and stress analysis. The numerical model is verified by comparing the field monitoring data with the finite element results. The study systematically analyzes the influence of reinforcement position, reinforcement parameters, and reinforcement depth on the maximum lateral displacement of the diaphragm wall of the foundation pit. The research results reveal that reinforcing the soil on both sides of the diaphragm wall can effectively reduce the lateral deformation of the foundation pit. Furthermore, the study shows that external reinforcement of the diaphragm wall can reduce the maximum lateral displacement of the wall to a certain extent, but the reinforcement effect is limited. The reinforcement effect of the inner side of the diaphragm wall improves with the increase of the excavation depth. Properly increasing the Young’s modulus of the reinforcement can reduce the adverse effect of excavation on the foundation pit. Finally, the optimal depth of reinforcement is found to be the excavation depth of the foundation pit of 28.2 m. The research results can provide a reference for the foundation pit reinforcement scheme in watery sandy soil areas.

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Section: Validation Of the Modelsupporting

confidence: 82%

Deformation Characteristics and Control Methods of Deep Foundation Pit Excavation in Watery Sandy Soil Area

Liu,

Zhan,

Zheng

et al. 2023

Advances in Frontier Research on Engineering Structures

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show abstract

“…Through numerical simulations and experiments, You et al [25] carried out a study on the appropriate thickness of the piezometric head of an upper pressurized aquifer, where the base of the pit was located to avoid the problem of uplift at the base of the pit. He et al [26] simulated the mechanical properties of a pile support structure under different combinations of excavation depths, support pile burial depths, and excavation widths, and they investigated the performance of the support structure under different excavation sizes with the help of finite element software.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study of Dig Sequence Effects during Large-Scale Excavation

Li,

Chen,

Dai

et al. 2023

Applied Sciences

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The appropriate excavation sequence can improve the overall stability of a foundation pit. In this study, eight schemes were created using FLAC3D to examine the impact of the excavation sequence on a foundation pit by analyzing a deep foundation pit in Nanjing, which had an irregular large rectangle shape. The results show that different excavation sequence schemes and different phases of the foundation pit can change the displacement values and the horizontal displacement type. The min–max normalization method was used to score the schemes in terms of six parameters and confirm the best excavation sequence scheme. In addition, the irregular shape of the foundation pit also leads to local differences in the stability of a foundation pit; the wide end is only slightly longer than the narrow end, but its displacement is significantly higher than that of the narrow end, so attention should be paid to reinforcing the weak parts when carrying out the support. This study can inform the selection of the excavation sequence for actual construction processes.

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Experimental study on stress and deformation characteristics of foundation pit considering excavation width using 3D printing technology

Liu,

Zhang,

Xiang

et al. 2024

Front. Earth Sci.

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A sophisticated model of the foundation pit support structure was developed via a model test that incorporated 3D printing technology. A meticulously scaled-down simulation of foundation pit excavation was conducted, utilizing the excavation width of the foundation pit as the sole variable, to evaluate and compare the impact of various foundation pit widths on the force and deformation characteristics of the foundation pit following layer-by-layer excavation. The findings indicate that the stress and deformation characteristics of the retaining structure shift from the “cantilever” mode to a composite mode of “internally convex” or “concave-convex” as the pit is excavated and internal support is installed. The change in pit width has minimal influence on the mechanical response law of the support structure during excavation. Nonetheless, the alteration in the pit width had a direct effect on both the internal force and deformation of the support structure, as well as the change in surface settlement value. In the experiment, wider pits had monitoring values that increased multiple times compared to narrower pits. The width of the foundation pit has a considerable impact on the mechanical response and stability of the pit, which is evident in the relatively lower lateral earth pressure on the outside of the retaining structure in narrower pits. This results in less stress and deformation of the pit structure. Moreover, the decrease in the passive zone of the pit contributes to better stability, indicating that the lower lateral earth pressure on the outside of the retaining structure is an innate reason for the excellent stability of narrower pits.

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Effect of Size on the Stability of Narrow Foundation Pits

Cited by 3 publications

References 9 publications

Deformation Characteristics and Control Methods of Deep Foundation Pit Excavation in Watery Sandy Soil Area

Deformation Characteristics and Control Methods of Deep Foundation Pit Excavation in Watery Sandy Soil Area

Numerical Study of Dig Sequence Effects during Large-Scale Excavation

Experimental study on stress and deformation characteristics of foundation pit considering excavation width using 3D printing technology

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