考虑施工扰动效应时大直径扩底桩纵向振动阻抗研究  

Longitudinal dynamic impedance of a large-diameter belled pile considering construction disturbance effect

作　　者：李振亚[1,2] 王奎华[1,2] 吴文兵[3] 

机构地区：[1]浙江大学滨海和城市岩土工程研究中心,浙江杭州310058 [2]浙江大学软弱土与环境土工教育部重点实验室,浙江杭州310058 [3]中国地质大学工程学院,湖北武汉430074

出　　处：《岩石力学与工程学报》2017年第A01期3678-3688,共11页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金面上项目(51378464;51579217);国家自然科学基金青年项目(51309207)~~

摘　　要：基于Rayleigh-Love杆模型研究考虑施工扰动效应时大直径扩底桩的纵向振动阻抗。首先,分别采用虚土桩模型和径向圈层间的剪切复刚度传递法考虑施工扰动造成的桩端以下土体的竖向非均质性和桩周土的径向非均质性;然后,求解桩–土界面的剪切复刚度,将其代入到桩的纵向振动控制方程中,通过Laplace变换和阻抗函数递推的方法,得到大直径扩底桩纵向振动频域响应解析解,在此基础上,通过与已有研究成果的对比,证明本文解的合理性;最后,通过参数分析的方法,在桩基动力设计中比较关心的低频范围内研究了桩的扩底参数以及施工扰动效应对大直径扩底桩纵向振动阻抗的影响,结果表明:(1)扩底半径对桩的动力特性的影响远大于扩底段长度的影响;(2)施工扰动效应对大直径扩底桩的动力特性影响显著,且桩周土扰动的影响要强于桩端以下土体扰动的影响。Based on the Rayleigh-Love rod model, the longitudinal dynamic impedance of a large-diameter belled pile is theoretically investigated considering the construction disturbance effect. First, the virtual soil pile model and the shear complex stiffness transfer method are adopted to simulate the vertical inhomogeneity of the pile end soil and the radial inhomogeneity of the surrounding soil caused by the construction disturbance effect, respectively. Then, the shear complex stiffness at the pile-soil interface is solved and is substituted into the goveming equation of the pile. Meanwhile, the analytical solution for the dynamic response at the pile head is obtained in the frequency domain by virtue of impedance function transfer method and Laplace transform method. On this basis, comparisons with published solutions are carried out to verify the reliability of the present solution. Finally, by means of parametric analysis method, the influence of pile parameters and the construction disturbance effect on the complex impedance at the pile head is investigated within the low frequency range concerned in the design of dynamic foundation. The results show that. （1） the influence of the radius of the enlarged base on the complex impedance at the pile head is much greater than that of the length of the enlarged base. （2） The dynamic characteristic of the large-diameter belled pile is greatly affected by the construction disturbance effect, besides, the influence of the disturbance of the pile surrounding soil is greater than that of the disturbance of the pile end soil.

关 键 词：桩基础 大直径扩底桩 纵向振动 复阻抗 施工扰动效应 剪切复刚度传递法 虚土桩 

分 类 号：TU473[建筑科学—结构工程]