Dynamic pile-side soil resistance during longitudinal vibration

Abstract

Accurate evaluation of dynamic resistance provided by the surrounding soil is the key to determining the dynamic performance of the pile foundation, especially for long piles. A new method is proposed to evaluate the dynamic pile-side soil resistance (DPSR). A dynamic coupled model of the pile-soil system is established considering the three-dimensional nature of the surrounding soil. Analytical solutions are then deduced for the dynamic response of each point along the pile shaft. The derived analytical solutions are then used to investigate several characteristics of the DPSR by analyzing the attenuation of the incident wave propagating along the pile shaft. The results show that the effect of DPSR decreases gradually from the pile top to tip under low-strain dynamic loading conditions, and it increases as the shear wave velocity of the surrounding soil increases between points under consideration along the pile shaft. It is also found that energy dissipation is the most important mechanism of soil resistance during longitudinal vibration associated with low strain axial loading, and thus damping should be evaluated carefully. The findings from this study aid in understanding the dynamic pile-soil interaction and provide practical guidance for analyzing the effect of the DPSR in engineering practice.