Abstract: By regarding the soil portion below the pile as a soil-pile and using the existed results of the soil resistance to horizontally vibrating pile, the dynamical behavior of the composite pile composed of the pile and virtual soil-pile, is analyzed; and the semi-analytical solutions for the dynamical stiffness of viscoelastic floating pile in a viscoelastic soil layer are obtained in the frequency domain. The variations of the stiffnesses with various physical parameters are shown in figures. Then, the influences of the material parameters on the stiffness are discussed; and the behavior differences between more slender and less slender piles are examined. It is shown that the dynamical stiffnesses of the floating piles depend on the pile length, soil property and excitation frequency. The results presented here are helpful for pile design.

Key words: floating pile, interaction between soil and pile, dynamical stiffnesses, horizontal vibration