自平衡试桩法桩基承载力等效转换新方法

发布时间：2018-05-06 03:01

本文选题：自平衡试桩法 + 剪切位移法　；参考：《铁道科学与工程学报》2016年12期

【摘要】：在分析自平衡试桩法桩基荷载传递机制的基础上,提出一种新的自平衡试桩法桩基承载力等效转换方法。该方法首先基于Mindlin公式求出桩侧摩阻力在桩周和桩底土体中引起的附加应力,通过考虑附加应力对桩侧土体极限侧摩阻力和桩-土界面初始剪切刚度的影响,并采用双曲线模型模拟桩-土界面剪切模量在桩基沉降过程中的动态变化来改进传统的剪切位移等效转换方法,使其适用于大变形的桩基沉降计算。进而,进一步通过对自平衡试桩法测试数据的反演分析,得到土体初始参数,从而转换获得等效的桩基在静载作用下的荷载-沉降曲线,并以此确定桩基承载力。该方法考虑土体的分层性、非线性、连续性和附加应力的影响,避免了在等效转换过程中引入经验系数。实例分析表明,该方法较既有规范中推荐的精确转换法具有更高的精确性,实际工程应用中,能够充分发挥桩基的实际承载能力。
[Abstract]:On the basis of the analysis of the load transfer mechanism of the self balanced pile test pile foundation, a new equivalent transformation method for the bearing capacity of the pile foundation is proposed. First, the additional stress caused by the side friction resistance of the pile in the soil around the pile and the pile bottom is calculated based on the Mindlin formula, and the ultimate friction resistance of the pile side to the pile side is considered by considering the additional stress. The effect of the initial shear stiffness of the pile soil interface and the hyperbolic model are used to simulate the dynamic change of the shear modulus of the pile soil interface in the pile foundation settlement process to improve the traditional shear displacement equivalent conversion method, so that it can be applied to the settlement calculation of the pile foundation with large deformation. Further, the inverse analysis of the test data of the self balanced pile test method is further passed. The initial parameters of soil are obtained, and the equivalent load settlement curve of pile foundation under static load is obtained, and the bearing capacity of pile foundation is determined by this method. The method considers the influence of soil layer, nonlinearity, continuity and additional stress, and avoids the introduction of empirical coefficient in the process of equivalent conversion. The exact conversion method recommended in the code has higher accuracy. In practical engineering application, the actual bearing capacity of pile foundation can be fully realized.

【作者单位】：中南大学土木工程学院;中国建筑第五工程局有限公司;山东省建筑科学研究院;
【基金】：国家自然科学基金资助项目(51508575) 中国博士后科学基金资助项目(2014M560652,2016T90764) 湖南省创新平台与科技人才资助项目(2015RS4006)
【分类号】：TU473.1

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