Numerical analysis of bearing capacity and conversion coefficient calculation of O-cell test of pipe pile in marine soft clay foundation
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摘要: 与传统桩基检测方法相比,自平衡试桩法可满足大吨位、水上试桩等特殊情况的需求,在近海及海上桩基检测中具有独特的优势。为研究滨海软土地基管桩自平衡法试桩过程的荷载传递特性,分析桩参数对转换系数的影响规律,通过建立桩土数值模型,分别模拟自平衡试桩和传统试桩过程,结合有限元法和等位移法,对转换系数和极限承载力进行计算,并讨论桩参数对转换系数的影响规律。研究结果表明:通过将等位移法引入自平衡桩土模型,计算得到等效转换的极限承载力与堆载法计算结果误差在0.5%以内,可准确计算自平衡转换系数,且管桩桩长和桩径增大会显著提高桩基承载力,桩参数对自平衡转换系数和桩基极限承载力具有显著影响。Abstract: Compared with traditional methods, O-cell test has unique advantages for some special sites, especially in the offshore pile foundation testing. To study the load transfer characteristics of the O-cell method for testing piles in coastal soft soil foundation, and analyze the influence of pile parameters on the conversion coefficient, this paper established the pile-soil numerical model to simulate the O-cell and traditional pile testing processes. The finite element method and equal displacement method were combined to calculate the conversion coefficient and ultimate bearing capacity, and the influence of pile parameters on the conversion coefficient was discussed. The research results indicate that the error between the equivalent conversion ultimate bearing capacity calculated by introducing the equal displacement method into the O-cell pile-soil model and the calculation results of the surcharge method is within 0.5%, and the O-cell conversion coefficient can be accurately calculated. The increase of the length and diameter of the pipe pile will significantly improve the bearing capacity of the pile foundation, and the pile parameters have a significant impact on the O-cell conversion coefficient and the ultimate bearing capacity of the pile foundation.
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Key words:
- O-cell test /
- pipe pile /
- Q-s curve /
- conversion coefficient
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表 1 桩土计算参数
材料 杨氏模量
/kPa泊松比 重度
/(kN·m−3)黏聚力
/kPa内摩擦角
/(°)软黏土层 15000 0.47 18.5 80 0 砂层 150000 0.35 20 30 25 基岩 1200000 0.25 23.5 400 34 桩 35000000 0.15 25 表 2 桩径影响分析方案
模型组 桩径
D/mm壁厚
t/mm桩长
L/m荷载箱距桩底
距离d/m极限加载
位移/mm长径比 1 500 130 20 5 25 40 2 600 130 20 5 30 33.3 3 1000 130 20 5 50 20 表 3 桩长影响分析方案
模型组 桩径
D/mm壁厚
t/mm桩长
L/m荷载箱距桩底
距离d/m极限加载
位移/mm长径比 4 1000 130 12 3 50 12 5 1000 130 16 4 50 16 6 1000 130 20 5 50 20 7 1000 130 24 6 50 24 -
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