基于虚拟加载上限法和黏土小应变特性的桩基<i>p</i>-<i>y</i>曲线

俞剑; 朱俊霖; 黄茂松; 沈侃敏

doi:10.11779/CJGE202111009

基于虚拟加载上限法和黏土小应变特性的桩基p-y曲线 English Version

俞剑^{1, 2,},
朱俊霖^{1, 2},
黄茂松^{1, 2, ,},
沈侃敏³

1.
同济大学地下建筑与工程系,上海　200092
2.
同济大学岩土及地下工程教育部重点实验室,上海　200092
3.
中国电建集团华东勘测设计研究院有限公司,浙江　杭州　310058

基金项目:

国家自然科学基金项目 51908420

国家自然科学基金项目 51579177

详细信息

作者简介:
俞剑(1987— ),男,助理研究员,博士,主要从事岩土工程方面的科研和教学工作。E-mail：002yujian@tongji.edu.cn

通讯作者:
黄茂松, E-mail：mshuang@tongji.edu.cn

中图分类号: TU470
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出版历程
- 收稿日期: 2021-03-08
- 网络出版日期: 2022-12-01
- 刊出日期: 2021-10-31

T-EMSD-based p-y curve of laterally loaded piles in clay considering small-strain behavior

YU Jian^{1, 2,},
ZHU Jun-lin^{1, 2},
HUANG Mao-song^{1, 2, ,},
SHEN Kan-min³

1.
Department of Geotechnical Engineering, Tongji University, Shanghai 200092, China
2.
Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education, Tongji University, Shanghai 200092, China
3.
Power-China Huadong Engineering Corporation Limited, Hangzhou 310058, China

摘要

摘要: 国际主流规范API推荐p-y曲线分析海上风电钢管桩基础的水平非线性响应。该p-y曲线通过单参数刻画了土体应力应变的发展规律从而间接控制桩土非线性响应。但因过度简化,在长期使用中已暴露出低估桩侧承载力,且无法准确预测桩土初始刚度等问题。为此,首先定义了含土体小应变特性的应力应变曲线,再基于虚拟加载上限法获得考虑该土体应力应变关系的数值p-y骨干曲线。结合参数分析,拟合得到二维p-y骨干曲线表达式。进一步结合三维极限承载力系数、桩土初始刚度和剪应变系数,将p-y骨干曲线拟三维化,并分别与三维有限元和工程实例对比验证其合理性。与API规范相比,该p-y骨干曲线不但准确预测桩侧承载力,对变形控制极严的海上风电钢管桩基础而言,其更显著优点在于通过考虑土体小应变特性实现准确预测桩土初始刚度。
- 水平受荷桩 /
- 软黏土 /
- p-y曲线 /
- 虚拟加载上限法 /
- 小应变
Abstract: The international popular API code recommends the p-y curve method to analyze the nonlinear behavior of offshore wind turbine (OWT) steel pipe piles. The p-y curve controls the pile-soil nonlinear response only through one parameter regarding the development of stress-strain relation of soils. This over-simplification results in the inaccurate evaluation of the lateral initial stiffness of pile-soil and the underestimation of the bearing capacity. Therefore, the stress-strain curve with soil small-strain behavior is first introduced to achieve a numerical p-y backbone curve by using the total-displacement-loading extended mobilized strength design method (T-EMSD). The expression for the two-dimensional p-y backbone curve is then fitted from the numerical results. The three-dimensional effect of the proposed p-y curve is further considered by incorporating the three-dimensional ultimate capacity factor, the initial subgrade modulus and the compatibility factor. The rationality of the proposed p-y curve is verified against the results from the three-dimensional finite-element analysis and field tests. Compared with API code, the proposed p-y curve can provide a more reasonable prediction for both the bearing capacity and the initial stiffness of pile-soil by considering the soil small-strain behavior, which is a significant advantage for the OWT pile foundation with strict deformation control.
- laterally loaded pile /
- soft clay /
- p-y curve /
- T-EMSD method /
- small strain

HTML全文

图 1 T-EMSD迭代示意图

Figure 1. Iteration diagram of T-EMSD method

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图 2 桩身荷载-位移曲线

Figure 2. Load-displacement curves of fully bounded pile

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图 3 分段示意图

Figure 3. Piecewise diagram of p-y curve

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图 4 拟合p-y曲线与T-EMSD方法对比

Figure 4. Comparison of p-y curves by fitting and T-EMSD

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图 5 水平受荷桩拟三维分析

Figure 5. Construction of p-y curve considering three-dimensional effects

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图 6 土体参数沿深度变化

Figure 6. Variation of soil parameters along depth

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图 7 p-y曲线对比（Winkler方法与有限元）

Figure 7. Comparison of p-y curves between Winkler and FEM

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图 8 现场试验1的p-y曲线对比

Figure 8. Comparison of p-y curves of field test Case 1

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图 9 现场试验2的p-y曲线对比

Figure 9. Comparison of p-y curves of field test Case 2

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表 1 剪应变系数 $M_{c}$ $M_{c}$

Table 1 Values of compatibility factor $M_{c}$ $M_{c}$

上限解	完全胶结	完全光滑
Klar^[18]（MSD：单层）	1.30	1.35
黄茂松等^[6]（T-EMSD：100层）	0.80	0.90

下载: 导出CSV

表 2 现场试验1土体参数

Table 2 Soil parameters of field test Case 1

深度z/D	$s_{u}$ $s_{u}$ /kPa	$G_{0}$ $G_{0}$ /MPa	$γ_{0.7}$ $γ_{0.7}$ /(10^-4)	$E_{50}$ $E_{50}$ /MPa
2	18	10	1	1.8
4	20	14	1	2

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表 3 现场试验2土体参数

Table 3 Soil parameters of field test Case 2

深度z/m	$s_{u}$ $s_{u}$ /kPa	$G_{0}$ $G_{0}$ /MPa	$γ_{0.7}$ $γ_{0.7}$ /(10^-4)	$E_{50}$ $E_{50}$ /MPa
3.6	13	12	4	0.87
6.3	15	15	4	1.0

下载: 导出CSV

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