考虑清淤策略的桩基时变可靠度分析

Time-dependent reliability analysis of pile foundations considering dredging strategies

  • 摘要: 为发展淤积岸坡-高桩码头相互作用体系结构可靠性分析方法,基于Fick第二定律推导了能考虑氯离子侵蚀效应的二维扩散模型,并采用时间离散法提出了一种综合考虑结构抗力衰减、淤积作用量化和预测,以及桩基受力变形分析的高桩码头桩基时变可靠度数值计算方法。并结合以目标可靠度为导向的清淤策略,编写了淤积岸坡-高桩码头体系时变可靠度外挂求解程序DPRP。在此基础上,开展了多工况计算分析,探讨了高桩码头桩基时变可靠度的演化规律。计算分析结果表明:码头近海侧桩基可靠度更易低于目标可靠度,在实际工程中需重点养护与修复;泥沙淤积作用会降低多数桩基时变可靠度,而对于近海侧及近岸侧且向岸倾斜的斜桩,其时变可靠度则会因泥沙淤积作用而增大。该高桩码头桩基时变可靠度数值求解流程框架及对应外挂子程序DPRP,可为高桩码头-岸坡相互作用体系的相关工程设计与可靠性评价提供参考。

     

    Abstract: To develop a structural reliability analysis method for the interaction system between silted slopes and high-piled wharves, a two-dimensional diffusion model considering chloride ion erosion effects was derived based on Fick’s second law. A time-discrete method was then employed to propose a numerical calculation method for the time-dependent reliability of pile foundations in high-piled wharves, comprehensively considering the degradation of structural resistance, quantification and prediction of siltation, and pile stress-deformation analysis. Additionally, a time-dependent reliability external solving program, DPRP, was developed for the silted slope-high-piled wharf system, incorporating dredging strategies guided by target reliability. Parametric analyses under multiple working conditions were conducted, exploring the evolution patterns of time-dependent reliability of pile foundations in high-piled wharves. The results show that the reliability of offshore pile foundations is more likely to fall below the target level, requiring focused maintenance and repair in practical engineering. While siltation generally reduces the time-dependent reliability of most pile foundations, it can increase the reliability of inclined piles on the offshore and nearshore sides that tilt toward the shore. This time-dependent reliability numerical calculation framework and the corresponding external program DPRP can provide a reference for engineering design and reliability assessment of high-piled wharf-slope interaction systems.

     

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