Abstract: A computational model for the seismic response of end-bearing pipe piles in saturated soil under vertically incident P-waves is established by considering the coupled vibration among pile, outer and inner soils. The soil is treated as a saturated two-phase medium, and the pile is modeled as a one-dimensional Euler bar. Considering wave scattering effects in the pile-soil system, the resultant soil displacements are expressed as the sum of scattered and free-field displacements. Based on the Biot’s dynamic consolidation theory, the governing equations of scattered and free-field soils are formulated, and expressions for the displacements and frictional forces of outer and inner soils are subsequently derived. Analytical solutions for the vertical seismic response of end-bearing pipe piles in saturated soil are obtained by incorporating soil frictional forces into the governing equation of the pipe pile and applying continuity and boundary conditions of the pile-soil system. The proposed solution is verified by comparing it to existing studies. Parameter analyses are conducted to examine the differences in seismic response of pipe piles in saturated versus single-phase soil and to investigate the influence of major pile-soil parameters in saturated soil on the seismic amplification factor at the pile top, kinematic response factor, and frictional forces of outer and inner soils.

Key words: seismic response, pipe pile, saturated soil, P waves