淤积条件下码头桩基-岸坡体系受力变形分析

Analysis of force deformation in wharf pile foundation-slope system under siltation conditions

  • 摘要: 沿海港口码头常受淤积影响,导致岸坡土体发生位移,进而威胁码头结构安全。结合具体工程建立了码头桩基-淤积岸坡相互作用有限元模型,以内力组合值判定桩基塑性变形状态,与码头桩基开裂轴线实际位置基本相符,验证了建模合理性。在此基础上,建立了桩-土相互作用简化模型,研究了淤积过程中桩基内力变化及桩-土体系位移演化趋势,分析了工程地质和码头结构方面因素对桩-土体系受力变形特征的影响规律。结果表明,岸坡淤积条件下,码头下方坡体水平位移及后方坡体竖向沉降较为明显;随着淤积土层厚度持续增加,岸坡稳定系数逐渐降低,而水平位移与竖向沉降逐渐增大,且变形量与淤积厚度呈线性关系。淤积过程中,各轴桩基水平位移沿纵向呈现相同变化趋势,而桩身弯矩分布则表现为3种不同模式;土体压缩模量对桩体位移和岸坡变形的影响最为显著,不同位置下影响桩顶弯矩变化的主导因素各异(或为压缩模量或为桩径),而淤积速度对桩-土体系受力变形状态的影响最小。本研究有助于完善岸坡淤积条件下桩-土相互作用理论体系,为工程实践中淤积码头的结构设计和日常维护提供理论支持。

     

    Abstract: Coastal port wharfs often suffer from siltation, leading to displacement of the slope soil and thereby threatening the structural safety of the wharf. A finite element model of the interaction between wharf pile foundation and silted slope was established, combining specific engineering scenarios. The plastic deformation state of pile foundations is determined by the internal force combination values, which roughly correspond to the actual position of the wharf pile foundation cracking axis, verifying the rationality of the modeling. On this basis, a simplified pile-soil interaction model was established to study the changes in internal forces in pile foundations during the siltation process and the evolution trend of displacement in the pile-soil system. Furthermore, the study analyzed the influence law of engineering geological and wharf structural factors on the force deformation characteristics of the pile-soil system. The results show that under slope siltation conditions, the horizontal displacement of the slope body under the wharf and the vertical settlement of the rear slope body are relatively obvious. As the thickness of the siltation soil layer continues to increase, the stability coefficient of the slope gradually decreases, while horizontal displacement and vertical settlement gradually increase, and the deformation is linearly related to the siltation thickness. During the siltation process, the horizontal displacement of various axial pile foundations shows the same trend longitudinally, while the bending moment distribution state of the pile body is presented in three different patterns; the soil compression modulus has the most significant impact on pile body displacement and slope deformation, with different leading factors affecting the bending moment change at the pile top (either the compression modulus or the pile diameter), while the siltation speed has the least impact on the force deformation state of the pile-soil system. This study contributes to the perfection of the theoretical system of pile-soil interaction under slope siltation conditions and provides theoretical support for the structural design and routine maintenance of silted wharfs in engineering practice.

     

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