Abstract Regarding the pile and the soil layer as viscoelastic media, the dynamical behavior of vertical vibration of an end-bearing viscoelastic pile in a viscoelastic soil layer is investigated in the frequency domain using methods of the Helmholtz decomposition and variable separation. The axisymmetric analytical solution for the vertical vibration of the pile is obtained, and the analytical expression for the dynamical complex stiffness of the pile top is presented. Responses of dynamic stiffness factor and equivalent damping of pile top with respect to the frequency are shown in figures by means of the numerical method. Influences of the soil’s viscosity, slenderness ratio of pile, modulus ratio of the pile to soil, pile’s Poisson ratio and viscosity on the stiffness factor and equivalent damping are examined. It is revealed that, due to the effect of the transversal deformation of the pile and the radial force of the soil acting on the pile, the dynamic stiffness factor and equivalent damping derived from the axisymmetrical solution are greatly different from those derived from the classic Euler rod model. Therefore, there are some limitations for the applicability of the Euler rod model for analysis of the vertical vibration of the pile, and the axisymmetric model based on the three dimensional viscoelasticity should be employed under some special cases.
2012, Vol. 33 
