大直径超长灌注桩水平承载性能的参数敏感性

大直径超长灌注桩是高规格建（构）筑物桩基工程的发展趋势，但有关其水平承载性能的研究还较少。依托江苏靖江文化中心大直径超长灌注桩建设项目，通过现场试桩试验获得了桩身水平受力及承载变形特征。采用孔压静力触探（CPTU）测试p-y曲线法构建了大直径超长灌注桩水平承载数值计算模型，在与现场试桩结果比对验证之后，进一步研究了桩径尺寸效应、桩顶嵌固形式、桩身倾角、竖向载荷对大直径超长灌注桩的影响规律。最后通过计算各影响因素的参数敏感度，实现了对大直径超长灌注桩水平承载性能参数敏感性的客观定量评价。研究结果表明：原位测试CPTU可以很好地应用于大直径超长灌注桩的水平承载分析，大直径超长灌注桩参数敏感度由大到小依次为：桩顶嵌固形式、尺寸效应、竖向荷载、桩身倾角。

Parameter sensitivity of horizontal bearing capacity of large diameter and super-long bored pile

The large diameter and super-long pile is the development trend of the pile foundation engineering of high standard buildings. But there is few research about its horizontal bearing characteristics. In this paper, the horizontal deformation and stress distribution of the large diameter and super-long pile were obtained by pile test in field of Jingjiang cultural center construction project. The piezocone penetration test (CPTU) p-y curve method was used to construct the numerical model of the large diameter and super-long pile under horizontal loading. After comparison and verification with the results of pile test, the numerical model was used to further study the influence of size effect, embedding types, inclination of pile and vertical loads on the horizontal bearing performance. Finally, the quantitative evaluation about the parameter sensitivity of the large diameter and super-long pile was achieved by calculation of different sensitivity values. The research results show that in-situ CPTU test is a very good application in analysis of horizontal bearing capacity of the large diameter and super-long pile, and the order of sensitivity values is: embedding type, size effect, vertical load, inclination.