Abstract: The lateral dynamic characteristics of a pipe pile in a viscoelastic soil layer are investigated. The soil is simulated using three-dimensional viscoelastic theory; and the pipe pile is modeled as an Euler-Bernoulli beam. The governing equations of the outer and inner soil are uncoupled without utilizing potential functions. The solutions are obtained by separate variable method. The lateral displacement of the pipe pile is derived based on the continuity conditions between the pipe pile and the soils. The lateral dynamic complex impedance of the pipe pile is determined. The proposed solution can be reduced to a solid pile solution. The proposed method is validated by comparing the calculated results with existing solutions. Parametric studies are conducted to study the influences of the moduli, densities of the outer and inner soil as well as the pile length on the complex impedance.

Key words: pipe pile, horizontal vibration, analytical solution, complex impedance, viscoelastic soil