This paper presents a closed-form solution on the steady dynamic response of circular piles embedded in inhomogeneous soil. The soil is modeled as a viscoelastic continuum, and the pile is modeled as a one-dimensional elastic shaft. Fictitious soil pile model and Hamilton’s energy principle are introduced to deduce the equations governing the layered pile–soil system. Impedance transfer method and iterative algorithm are deduced to decouple the pile–soil dynamic interaction. The results show that the modulus and thickness of inhomogeneous soil profile play a more significant role in the dynamic stiffness than the damping effects. The variation pattern of the dynamic impedance against the modulus of layered soil is dominated by the cut-off frequency. Particularly, in Gibson soil, the stiffer surface soil yields the greater pile-head stiffness. The dynamic stiffness of piles in Gibson soil could be approximated by two or more soil layers with equivalent Young’s modulus.

本文提出了一个关于嵌入非均质土壤中的圆形桩的稳态动力响应的封闭形式的解决方案。土壤被建模为粘弹性连续体，桩被建模为一维弹性轴。引入虚拟土桩模型和哈密顿能量原理，推导了分层桩土系统的控制方程。推导出阻抗传递方法和迭代算法来解耦桩土动力相互作用。结果表明，与阻尼效应相比，非均匀土剖面的模量和厚度对动态刚度的影响更为显着。动态阻抗相对于层状土壤模量的变化模式由截止频率决定。特别是在 Gibson 土壤中，较硬的表层土壤产生较大的桩头刚度。