Influence of pile end soil on the torsional vibration of a pile based on the cone-shaped fictitious soil pile model considering the stress diffusion

This study is concentrated on the influence of the pile end soil on the torsional vibration of a pile based on the fictitious soil pile model considering the stress diffusion. The pile end soil is simulated as a cone-shaped fictitious soil pile whose parameters still remain the same with the soil. The dynamic equilibrium equations for the pile–soil system subjected to torsional dynamic loadings are developed and are solved to obtain the corresponding analytical solution. Then, comparisons with other solutions are conducted to verify the reliability of the proposed solution. Finally, parametric analysis results are presented based on the proposed solution to portray the influence of the stress diffusion angle, thickness and shear wave velocity of the pile end soil.