The influence of a fixed axial top load on the dynamic response of a single pile

Abstract

The influence of the gravity and inertia of a concentrated mass attached to the top of a single pile on the pile’s dynamic response was investigated in this study. Based on Muki’s fictitious pile method, the static initial axial force of the pile caused by the gravity of the concentrated mass was calculated first. Using the obtained initial axial force of the pile and taking into account the influence of the inertia of the concentrated mass, the second kind of Fredholm integral equations describing the dynamic response of the preloaded single pile were established via the fictitious pile method. Using the obtained integral equations, the dynamic response of the preloaded single pile to an incident Rayleigh wave was calculated. The influence of the pile–soil Young’s modulus ratio, the frequency of the incident Rayleigh wave and the pile length on the dynamic response of the preloaded pile was examined. The numerical results of this study show that the concentrated mass attached to the top of the pile will affect both the dynamic axial and shear forces of the pile. Generally, the concentrated mass attached to the pile top has a greater influence on the shear force of the pile than on the axial force.