杨志浩, 程世奥, 岳祖润, 冯怀平, 赵得杰, 马德良, 李同海. 锥形桩冻拔特性多因素影响规律及抗拔机理研究[J]. 岩土工程学报, 2025, 47(7): 1382-1391. DOI: 10.11779/CJGE20240657
    引用本文: 杨志浩, 程世奥, 岳祖润, 冯怀平, 赵得杰, 马德良, 李同海. 锥形桩冻拔特性多因素影响规律及抗拔机理研究[J]. 岩土工程学报, 2025, 47(7): 1382-1391. DOI: 10.11779/CJGE20240657
    YANG Zhihao, CHENG Shi'ao, YUE Zurun, FENG Huaiping, ZHAO Dejie, MA Deliang, LI Tonghai. Multifactorial influence patterns and resistance mechanisms of frost-jacking characteristics in conical piles[J]. Chinese Journal of Geotechnical Engineering, 2025, 47(7): 1382-1391. DOI: 10.11779/CJGE20240657
    Citation: YANG Zhihao, CHENG Shi'ao, YUE Zurun, FENG Huaiping, ZHAO Dejie, MA Deliang, LI Tonghai. Multifactorial influence patterns and resistance mechanisms of frost-jacking characteristics in conical piles[J]. Chinese Journal of Geotechnical Engineering, 2025, 47(7): 1382-1391. DOI: 10.11779/CJGE20240657

    锥形桩冻拔特性多因素影响规律及抗拔机理研究

    Multifactorial influence patterns and resistance mechanisms of frost-jacking characteristics in conical piles

    • 摘要: 为探究锥形桩冻拔特性演变特征及抗拔机理,研发锥形桩抗冻拔性能测试装置,开展单向冻结下锥形桩冻拔试验,分析桩体材质、锥角、桩周土含水率及冻融循环对锥形桩冻拔性能的影响规律,讨论锥形桩抗拔机理。表明:同等条件下,桩体冻拔位移随锥角增大呈指数形式递减;随冻融循环次数增大,直柱桩冻拔位移增长速率呈半对数形式增长,而锥形桩变化不明显;桩体材质对锥形桩冻拔特性影响显著,且木质桩体会发生融拔现象;单向冻结过程中桩周土内部水分由底部向上迁移,初始含水率越大,水分迁移越明显,桩体冻拔位移越大,但含水率对冻拔位移影响程度弱于锥角;桩周土冻结过程中冻深增大,桩体表面切向冻胀力增大、法向冻胀力由压应力逐渐减小并转换为拉应力,当上述两个力分别大于桩土切向冻结强度和极限法向抗拉强度时,桩体发生冻拔。综合考虑抗冻拔、经济性及对冻土保护,抗冻拔锥形桩锥角宜设计为7°~9°,但仍需考虑桩深参数。

       

      Abstract: To investigate their evolution characteristics of frost-jacking behavior and their resistance mechanisms, a testing device for the anti-frost-jacking performance of conical piles is developed. The unidirectional freezing tests on the conical piles are conducted to analyze the effects of pile materials, cone angles, soil moisture contents around the piles and freeze-thaw cycles on their frost-jacking performance as well as their anti-frost-jacking mechanisms. It is indicated that under the same conditions, the frost-jacking displacement of the piles decreases exponentially with the increase in the cone angles. As the number of freeze-thaw cycles increases, the growth rate of the frost-jacking displacement for vertical piles increases in a semi-logarithmic manner, while changes in the conical piles are not significant. The pile materials have a significant impact on the frost-jacking characteristics of the conical piles, and the wooden pile may experience thawing extraction. During the unidirectional freezing process, the moisture within the soil surrounding the piles migrates upward from the bottom. The greater the initial moisture contents, the more pronounced the migration, leading to larger frost-jacking displacements. However, the effects of the moisture contents on the frost-jacking displacement are weaker than those of the cone angles. During the freezing process of the soil around the piles, the freezing depth increases, the tangential frost-jacking force on the pile surface increases, and the normal frost jacking force gradually decreases from compressive stress to tensile one. When these two forces exceed the tangential freezing strength of the soil and the ultimate normal tensile strength, the frost-jacking of the piles occurs. Considering the resistance to frost jacking, economic factors and the protection of frozen soil, the cone angles of the anti-frost-jacking conical piles should be designed to be between 7° and 9°, but the pile depth must also be taken into account.

       

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