| 摘要: |
| 针对岩土参数不确定性对单桩水平承载力的影响，以及水平荷载波动引起的单桩设计方案水平承载力考虑不足问题，提出基于可靠度理论的单桩水平承载力鲁棒性设计思路。先将岩土参数和水平荷载作为不确定因素，利用平均值及标准差考虑参数变异性；其次将桩身几何尺寸、配筋率及混凝土强度作为设计参数，同时考虑桩顶边界条件，按照抵抗桩顶水平位移的挠度失效模式与抵抗桩身弯矩的强度失效模式作为目标函数进行单桩水平承载力设计。鲁棒性设计避免了传统设计忽略岩土参数不确定的不合理问题，将鲁棒性作为安全性评价标准，结合经济性对水平承载桩基进行多目标优化设计。通过与传统设计对比分析，证明了鲁棒性设计的合理性与重要性。分析表明：桩径和配筋率的增加可显著提高单桩水平承载力，而桩身混凝土强度对抵抗桩顶位移的作用并不明显且经济性较差。 |
| 关键词: 水平承载桩 Pasternak双参数地基 不确定性 鲁棒性 经济性 |
| DOI： |
| 分类号:TU473 |
| 基金项目:国家自然科学基金资助项目（51278244）；江苏省2015年度普通高校研究生科研创新计划项目(KYLX15_0807) |
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| Robust geotechnical design and analysis of horizontal bearing capacity of laterally loaded pile |
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ZHANG Feng1,2, WANG Xudong1, ZHOU Feng1, CHENG Jianyang1
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1.College of Transportation Science & Engineering, Nanjing Tech University, Nanjing;2.CSCEC Strait Construction and Development Co., Ltd., Fuzhou
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| Abstract: |
| The horizontal bearing capacity of the laterally loaded pile is influenced by the uncertainty of soil parameters and the fluctuation of the horizontal loads will increase the risks of failure of the pile. In order to solve these problems, a robust geotechnical design （RGD） based on the reliability is presented in this study as a new geotechnical design concept. First, the mean and standard deviation of the soil parameters are investigated to clarify the uncertainty of the soil parameters in the RGD method. And then the size of the pile, the reinforcement ratio and the concrete strength are taken into consideration as the design parameters, and the boundary conditions of the pile top are also analyzed. The horizontal deflection failure modes （DFM） and the resistance of bending moment strength failure modes （SFM） of the pile top are used as a target function in the design of the horizontal bearing capacity of a single pile. As a safe evaluation standard, the design robustness is used to evaluate the feasibility of the design scheme for the horizontal bearing capacity of the single pile with the RGD method. By use of the RGD approach, the cost efficiency and robustness are the optimun target to achieve the multi-objective engineering optimization. The design scheme satisfies the bearing capacity requirements. Meanwhile, the cost efficiency and robustness of the design are guaranteed. Comparing with the traditional design methodology, the rationality and importance of the RGD are proved in this study. Analysis results show that the increase of the pile diameter and the reinforcement ratio can significantly improve the horizontal bearing capacity of the single pile, but the effect of the concrete strength of the pile shaft on the resistance to the pile head displacement is not remarkable and its economic benefit is poor. |
| Key words: laterally loaded pile Pasternak double-parameter foundation uncertainty robustness cost efficiency |
