成层饱和土中桩纵向振动特性研究及应用

采用Winkler地基模拟土层间的相互作用,建立了三维轴对称条件下饱和成层土中弹性支承桩纵向振动的简化模型,通过势函数分解和分离变量方法得到饱和土层的振动形式解,进而利用桩土完全接触条件求解出任一桩段的耦合振动解,根据复阻抗传递原理得出桩顶频域响应解析解和时域响应半解析解,在此基础上,分析了分层模型的合理性以及土层参数对桩顶动力响应的影响,最后结合工程实例对比了分层模型和单层模型,结果表明,采用分层模型可以取得更好的拟合效果。

A STUDY ON LONGITUDINAL PILE VIBRATION IN SATURATED LAYERED SOIL AND ITS APPLICATION

A simplified model of longitudinal pile vibration in saturated layered soil is developed using Winkler foundation model to simulate the interaction of soil layers. The solutions of saturated soil layer are derived by means of decomposition of displacement potential and separation of variables. And the coupled dynamic solutions of an arbitrary pile segment are obtained in terms of perfect contact hypothesis on the shaft surface. Then, the analytical solutions in frequency domain and the semi-analytical solutions in time domain at pile head are presented based on the theory of complex resistance transmission. Furthermore, the rationality of the above model and effects of the soil parameters on dynamic responses at the pile head are analyzed. Finally, a field dynamic pile testing is used to verify the validity of the layered model. The results show that the present model is better than the single layer model.