The problem of dynamic pile-soil interaction and its modeling through the concept of a Dynamic Winkler Foundation are revisited. It is shown that depth-dependent Winkler springs and dashpots, obtained by dividing the complex-valued soil shear tractions and the corresponding displacements along the pile, may faithfully describe pile-soil interaction, contrary to common perception that the Winkler model is always approximate. A theoretical wave model is then derived for analyzing the response of axially loaded endbearing piles embedded in a homogeneous viscoelastic soil medium. Closed-form solutions are obtained for: (i) the displacement field in the soil and along the pile; (ii) the impedance coefficients (stiffness and damping) at the pile head; (iii) the depth-dependent Winkler moduli along the pile; (iv) the average, depth-independent, Winkler moduli to match the impedance coefficient at the pile head. Results are presented in terms of dimensionless graphs and charts that highlight the salient features of the problem. The predictions of the model compare favorably with established solutions from the literature, while new results are presented
