Analysis of lateral dynamic responses of end-bearing friction pipe pile considering the second-order effect

Abstract

In this study, the impact of the second-order effect on the pipe pile's lateral dynamic responses is investigated by Novak's thin layer method. To derive the pile's axial force function, the vertical static equilibrium equations governing the pipe pile expressed in terms of displacements are rigorously solved. The lateral motion equations of the inner and outer soils are decoupled by introducing the potential functions, and the lateral soil resistance is subsequently determined. The pipe pile is idealized as an Euler-Bernoulli beam embedded within a half-space continuum. Based on the lateral vibration equilibrium equation, the solution for the pipe pile's dynamic responses is theoretically derived. By comparisons with the existing theoretical solutions in the absence of vertical loads, the correctness of the solution is verified. Parametric analysis is executed to delve into the impacts of side friction, vertical load, pile-soil modulus ratio, dimensionless frequency, Poisson's ratio, as well as length-diameter ratio on the lateral dynamic responses. Our results indicate that neglecting side friction leads to an overestimation of internal forces, including bending moments and shear forces; vertical load redistributes the pipe pile's displacements and internal forces.