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李立辰, 刘卓, 刘浩, 吴文兵, 罗仑博, 蒋国盛, 梅国雄. 考虑土塞效应的开口管桩沉桩与承载全过程离散元分析[J]. 岩土工程学报. DOI: 10.11779/CJGE20230340
引用本文: 李立辰, 刘卓, 刘浩, 吴文兵, 罗仑博, 蒋国盛, 梅国雄. 考虑土塞效应的开口管桩沉桩与承载全过程离散元分析[J]. 岩土工程学报. DOI: 10.11779/CJGE20230340
DEM analysis on the installation and bearing process of open-ended pile considering plugging effect[J]. Chinese Journal of Geotechnical Engineering. DOI: 10.11779/CJGE20230340
Citation: DEM analysis on the installation and bearing process of open-ended pile considering plugging effect[J]. Chinese Journal of Geotechnical Engineering. DOI: 10.11779/CJGE20230340

考虑土塞效应的开口管桩沉桩与承载全过程离散元分析

DEM analysis on the installation and bearing process of open-ended pile considering plugging effect

  • 摘要: 开口管桩贯入过程中会产生复杂的土塞效应,显著影响管桩的沉桩过程与承载特性。考虑到试验方法成本高、周期长、且难以直观反映土塞与管桩的相互作用特性,本文基于离散元方法开展砂土地基中静压开口管桩沉桩与承载全过程模拟分析。基于室内试验数据对离散元模型参数进行标定,并采用周期性单元复制法生成均质且应力沿深度线性分布的地基模型。基于土体变形特征,揭示管桩中土塞的主动拱与被动拱分布特征。进一步地,结合土塞参数的演化规律,得出土塞增长率(IFR)对土塞状态变化更为敏感,且土塞阻力的发挥趋势与IFR值变化趋势有较高的相似性。基于管桩静载试验模拟,得出静载下开口管桩呈完全闭塞状态,土塞的荷载-位移响应呈弹塑性,并最终建立考虑锥尖阻力、土塞效应、管桩尺寸的静压开口管桩桩端阻力经验计算公式。本文研究成果揭示了土塞的形成演化过程与承载机制,对于考虑土塞效应的开口管桩沉桩阻力预测与承载力计算具有一定参考价值。

     

    Abstract: The penetration process of open-ended pile would cause complex plugging effect, which further influences the pile installation and bearing characteristics. Considering the high cost、long period and limitations in reflecting the interaction between pile and soil plug of the traditional experimental approach, the jacking installation and subsequent loading process of open-ended pile in sand is simulated based on Discrete Element Method (DEM). The Periodic cell replication method is applied to generate a homogeneous foundation sample with linear stress distribution. Based on the analysis of the soil deformation characteristics, the characteristics of the active arch and passive arch distribution of the soil plug is revealed. Based on the analysis of the evolution of soil plug parameter and plug bearing characteristics, it is found that the incremental filling ratio (IFR) is more sensitive to the plug behavior and the development of plug resistance shows good consistency with the trend of IFR value. Also, the open-ended pile is in the fully plugged mode under static load and the load-displacement response of soil plug is elastic-plastic. Finally, the calculation method of end bearing capacity of open-ended jacked pile is constructed by considering the CPT cone resistance、plugging effect and pile size effect. The above results reveal the evolution process and bearing mechanism of soil plug and could provide some reference value for the prediction of installation resistance and calculation of bearing capacity of open-ended pile considering soil plugging effect.

     

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