Vertical Kinematic Response of End-Bearing Pipe Piles in Saturated and Nearly-Saturated Soil

Abstract

A mathematical formulation is presented in this paper to investigate the kinematic response of end-bearing pipe piles in two-phase poroelastic medium under vertically propagating seismic P-waves. The outer and inner two-phase soil are modelled as either fully saturated or nearly-saturated medium that obeys Biot’s poroelastodynamic theory, by considering the absence or presence of air inclusions in the pore fluid. Closed-form expressions for the pile displacement and kinematic response factor are obtained, which are employed to study the kinematic response in fully saturated and nearly-saturated soil for different problem parameters. Through analysis of the results, we demonstrate that seismic analysis models of pile considering only full saturation of two-phase soil may significantly underestimate soil-pile kinematic interaction if nearly-saturated conditions are ignored.

Keywords: kinematic response, pipe piles, poroelastic soil, analytical solution, P waves