Study on the pullout bearing characteristics of bio-inspired root piles in coral sand foundation under different root buried depths

Abstract

Bio-inspired root pile (abbreviated as root pile) is a new type of bio-inspired foundation, which has a broad application prospect in the development and construction of China's South China Sea area due to its good bearing characteristics such as pullout bearing capacity. The effect of root buried depth on the uplift bearing characteristics of root piles is analyzed through the model test of uplift bearing of root piles with different root buried depths in coral sand foundation. The results show that increasing the root buried depth can improve the ability of the root pile to control the uplift displacement, and there exists an optimal buried depth or range of buried depths that can effectively improve the pile foundation's uplift bearing capacity and control the ultimate displacement. The attenuation of axial force at the root is in the form of a step; with the increase of root buried depth, the maximum value of lateral friction resistance develops from the lower part of the pile body without root to the upper part of the pile body without root. The range of the bearing ratio of the root section of the pile with root buried depth of 260 mm, 340 mm and 420 mm is 12.33%-15.68%, 9.98%-17.82% and 7.61%-21.65%, respectively; the smaller the root buried depth is, the higher is the ratio of the bearing ratio of the root section at the beginning of loading, and the bigger the root buried depth is, the bigger is the ratio of the root's final bearing ratio. The change of soil pressure around the pile increases and then decreases, and the densest point of soil compacting moves upward with the increase of root buried depth. The research results provide scientific basis for the design of root pile buried depth and root arrangement in actual projects.

Keywords

Bio-inspired root piles (Root pile) / Coral sand / Pullout resistance / Root buried depth / Bearing characteristic

CRediT authorship contribution statement

Xiangwei Fang: Writing - review & editing, Supervision, Project administration, Methodology, Funding acquisition, Formal analysis, Data curation. Yaoyi Zhang: Writing - review & editing, Writing - original draft, Methodology, Investigation, Formal analysis, Data curation. Zhiqiang Wang: Writing - review & editing, Writing - original draft, Methodology, Investigation, Formal analysis, Data curation. Peixi Xiong: Formal analysis, Data curation. Fenghui Hu: Investigation, Data curation. Ganggang Zhou: Investigation. Chunyan Wang: Investigation.

Data availability

Data will be made available on request.

Declaration of Competing Interest

Yaoyi Zhang is employed by CCCC Yangtze River Construction Development Group Co., Ltd., and the other authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

The research was financially supported by National Natural Science Foundation of China (No. 51978103, No. 52408355), the Postdoctoral Fellowship Program of CPSF (No. BX20240450), and Chongqing Talent Innovation and Entrepreneurship Demonstration Team (No. cstc2024ycjh-bgzxm0012), the authors gratefully acknowledge this financial support.

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