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Journal of Zhejiang University SCIENCE A
ISSN 1673-565X(Print), 1862-1775(Online), Monthly
2025 Vol.26 No.11 P.1021-1033
Reliability-based optimization of laterally loaded piles with necking defects
Abstract: Laterally loaded piles, which are commonly used in sandy stratum foundations, are particularly susceptible to necking defects during cast-in-place installation due to borehole collapse risks. These construction-induced geometric imperfections substantially compromise pile safety under lateral loading conditions. To address this critical design challenge, we develop a reliability-based multi-objective optimization framework that simultaneously accounts for structural safety, construction economy, and design robustness. The proposed methodology integrates the p-y curve (where p is the soil pressure per unit length, and y is the lateral deflection of the pile) analysis with stochastic modeling, enabling efficient evaluation of pile performance considering uncertainties in soil parameters and depth and size variations of necking defects. A systematic design framework is implemented and validated through experimental case studies, successfully generating optimal designs along the Pareto front. The identified knee-point configurations serve as practical compromise solutions for engineering decisions. Parametric investigations further elucidate the influence of necking defect depth and sand friction angle variations on optimal design outcomes, offering insights into risk mitigation for pile construction.
Key words: Necking defect; Laterally loaded pile; Soil parameter uncertainties; Foundation construction design; p-y curve analysis; Stochastic modeling
机构:1浙江大学,海洋学院,中国舟山,316021;2浙江大学海南研究院,中国三亚,572025;3浙江大学,建筑工程学院,中国杭州,310058;4中国能源建设集团浙江省电力设计院有限公司,中国杭州,310012
目的:侧向受荷桩广泛应用于砂土地基基础中,但其现浇施工易因钻孔塌孔引发颈缩缺陷,导致桩基在侧向荷载作用下的安全性显著降低。针对这一关键设计难题,本研究旨在开发一种基于可靠性的多目标优化设计框架,以平衡桩基础安全性、经济性与设计鲁棒性,减少颈缩缺陷影响。
创新点:1.提出了一种融合p-y曲线分析与随机模拟的高效方法,实现了对砂土参数、颈缩缺陷深度与尺寸变异等多源不确定性的量化评估;2.通过构建可靠性多目标优化框架,将桩身性能、成本控制及抗风险能力纳入统一设计体系,突破了传统单目标优化局限。
方法:1.集成随机建模与数值仿真技术,建立考虑土体参数空间变异性和颈缩缺陷几何随机性的桩-土相互作用计算方法(图1和2);2.通过系统化的设计框架,结合帕累托前沿优化算法生成备选优化方案,利用实验案例验证模型有效性(图8);3.开展参数敏感性分析,揭示颈缩缺陷深度与砂土摩擦角对最优设计的影响规律(图9~12)。
结论:1.基于电子表格计算方法,实现了综合考虑成本、安全性与稳健性的含颈缩缺陷的侧向受荷桩优化设计;2.该方法可在设计阶段主动应对颈缩缺陷影响,提升工程可靠性;3.发现缺陷埋深对设计稳健性有显著影响:当颈缩缺陷位于桩体深处(埋深大于0.4倍桩长)时,基于桩身内力分布特性,缺陷对整体稳健性的影响可忽略。
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DOI:
10.1631/jzus.A2400484
CLC number:
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On-line Access:
2025-11-24
Received:
2024-10-21
Revision Accepted:
2025-05-01
Crosschecked:
2025-11-25