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.