考虑桩身横向惯性效应和桩周土竖向支承作用的楔形管桩纵向振动特性

Longitudinal vibration characteristics of a tapered pipe pile considering the transverse inertia effect and the vertical supporting of the surrounding soil

该文研究考虑桩身横向惯性效应和桩周土竖向支承作用的楔形管桩纵向振动特性。首先,根据楔形管桩特殊的桩身结构和桩周土的成层性,将桩-土系统沿纵向划分为若干微元段,采用Voigt体模型模拟桩周土对楔形管桩桩段的竖向支承作用;基于考虑土体竖向波动效应的三维轴对称模型建立桩周土纵向振动控制方程并求解,得到桩-土之间的侧摩阻力;然后,基于Rayleigh-Love杆模型建立桩的纵向振动控制方程以考虑其横向惯性效应,求解桩的振动控制方程并结合Laplace变换和阻抗函数递推,得到考虑桩周土竖向支承作用的桩顶复阻抗和速度导纳解析解,进一步地,通过卷积定理和Fourier逆变换得到桩顶时域响应半解析解;最后,通过与已有解的对比验证了该文解的合理性,并通过参数分析的方法研究了桩身横向惯性效应、桩周土竖向支承作用及桩身参数对桩顶动力特性的影响。

The longitudinal vibration characteristics of a tapered pipe pile was investigated considering the transverse inertia effect of the pile and the vertical supporting of the surrounding soil.First,the pile-soil system was partitioned into finite segments in the vertical direction to consider the special structure of the tapered pipe pile and the stratification of the surrounding soil.The Voigt model was employed to simulate the vertical supporting of the surrounding soil on the pile shaft.The dynamic governing equation for the surrounding soil was built based on the three-dimensional axisymmetric model that only considered the vertical wave effect of the soil and was solved to derive the frictional force on the pile-soil interface.Then,the dynamic governing equation for the pile was established based on the Rayleigh-Love rod model considering the transverse inertia effect of the pile.By solving the dynamic governing equation of the pile and together with the Laplace transform and impedance function transfer method,the analytical solutions for the complex impedance and the velocity admittance considering the vertical supporting of the surrounding soil were derived.Further,the semi-analytical solution in the time domain was derived by virtue of the convolution theorem and inverse Fourier transform.Finally,the reliability of the present solution was verified by comparing with the published solution.Based on the present solution,a parametric analysis was conducted to analyse the influence of the pile transverse inertia effect,the vertical supporting of the surrounding soil and the pile parameters on the dynamic characteristics at the pile head.