基于海上风电试桩数据的大直径桩<i>p</i>–<i>y</i>模型研究

王卫; 闫俊义; 刘建平

doi:10.11779/CJGE202106017

基于海上风电试桩数据的大直径桩p–y模型研究 English Version

1.
中国长江三峡集团有限公司科学技术研究院,北京　100038
2.
中国三峡新能源（集团）股份有限公司,北京　100053

基金项目:

清华大学水沙科学与水利水电工程国家重点实验室开放基金项目 sklhse-2020-C-06

中国长江三峡集团有限公司科研项目 WWKY-2020-0735

详细信息

作者简介:
王卫(1992—),男,工程师,博士,主要从事海上风电桩基础、胶结颗粒料科研工作。E-mail: wangwei16@tsinghua.org.cn

中图分类号: TU473
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出版历程
- 收稿日期: 2020-08-09
- 网络出版日期: 2022-12-02
- 刊出日期: 2021-05-31

Study on p-y models for large-diameter pile foundation based on in-situ tests of offshore wind power

1.
Institute of Science and Technology, China Three Gorges Corporation, Beijing 100038, China
2.
China Three Gorges Renewables (Group) Co., Ltd., Beijing 100053, China

摘要

摘要: 近海风电基础结构以大直径钢管桩为主,然而采用的设计方法仍是基于海上油气平台小直径桩试桩试验总结提出的p–y模型,其预测结果相对保守,可靠性值得商榷。鉴于此,提出一种综合考虑桩径和地层深度影响的黏土p–y修正模型,基于海上风电原位试桩数据对比分析API规范推荐的黏土p–y模型和砂土p–y模型,以及黏土p–y修正模型对水平受荷桩的桩侧土体抗力、桩身变形和桩身弯矩预测的准确性。研究结果表明：API规范推荐的黏土p–y模型显著高估了淤泥混砂和黏土的桩周土体抗力,砂土p–y模型的预测值比实测值约高一个数量级；黏土p–y修正模型对淤泥混砂和黏土的桩侧土体抗力有很好的预测性；基于黏土p–y修正模型和Sorensen等提出的砂土p–y模型能够较精准地预测海床地基中的桩身变形和桩身弯矩。
- 海上风电 /
- 水平受荷桩 /
- 原位试桩试验 /
- p–y模型
Abstract: Large steel pipe pile is the most commonly used foundation structure for offshore wind power. However, the adopted design methods for large-diameter piles are p-y models, which are originally proposed based on many small-diameter pile tests for offshore oil and gas platforms. The prediction precision of the p-y models is relatively conservative, and its reliability is not clear. Thus, a modified p-y model for clay is proposed considering the influences of pile diameter and soil layer depth. Based on the data of in-situ pile tests of offshore wind power, the accuracies of p-y models for clay and sand recommended by the API code and modified p-y model for clay to predict the lateral soil resistance, pile deformation and bending moment of laterally loaded piles are analyzed and compared. The results show that the p-y model for clay recommended by the API code significantly overestimates the soil resistance of silt-sand and clay soil, and the predicted value using the p-y model for sand is about an order of magnitude higher than the measured one. The modified p-y model for clay can precisely predict the soil resistance of silt-sand and clay soil. Based on the modified p-y model for clay and p-y model sand proposed by Sorensen, the deformation and bending moment of piles in multi-layer seabed can be precisely predicted.
- offshore wind power /
- laterally loaded pile /
- in-situ pile test /
- p-y model

HTML全文

图 1 p–y曲线和 $σ$ – $ε$ 曲线对比图

Figure 1. Comparison between p–y and $σ$ – $ε$ curves

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图 2 试桩点地层分布

Figure 2. Soil layers at site of test pile

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图 3 试桩平面布置图

Figure 3. Plane arrangement of test piles

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图 4 试桩加载点的水平荷载–位移曲线

Figure 4. Lateral load-displacement curves at head of test piles

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图 5 API黏土p–y模型的预测值与实测值的比较

Figure 5. Comparison between measured values and p–y curves model recommended by API

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图 6 修正黏土p–y模型的预测值与实测值的比较

Figure 6. Comparison between measured values and proposed p–y curves model

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图 7 砂土p–y模型的预测值与实测值的比较

Figure 7. Comparison between measured values and for p-y curves model

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图 8 4种方法的K_i随地层深度变化趋势

Figure 8. Variation of K_i distribution with depth by four methods

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图 9 桩身变形和弯矩的对比

Figure 9. Comparison among measured lateral displacements

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表 1 岩土材料参数

Table 1 Properties of soil materials

土层名称	$γ$ /(kN·m^-3)	c_u/kPa	$ε_{50}$ /%	$φ$ /(°)	E_s/MPa	f_ak/kPa
淤泥混砂	17.4	15	2.0	—	—	50
黏土	18.0	35	2.0	—	—	100
中细砂	21.0	—	—	33.8	35	270
砂卵砾石	21.5	—	—	42.0	60	—
注： $γ$ 为饱和重度；c_u为不排水抗剪强度, $ε_{50}$ 为黏土50%应力水平时对应应变值； $φ$ 为内摩擦角；E_s为压缩模量；f_ak为承载力特征值。

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表 2 试桩试验参数

Table 2 Parameters of test piles

编号	桩径/m	桩长/m	壁厚/mm	桩顶标高/m	桩底标高/m
SZ1	2.0	78.5	30	6	-72.5
SZ2	2.0	82.0	30	6	-76.0

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