Improved Fictitious Soil Pile Model for Simulating the Base Soil Under the High-Strain Condition

Abstract

The dynamic pile-soil interaction significantly affects the accuracy of pile vibration response analysis. However, currently, there is no well-established method for simulating pile toe soil under high-strain dynamic loading (HSDL), which presents a major challenge for pile driving analysis. This paper proposes a fictitious soil pile model to simulate reactions and stress wave propagation in the base soil under HSDL. The pile toe soil was regarded as a fictitious soil pile extending downward to the bedrock at a certain cone angle, considering the non-linear soil stiffness, radiation damping, and hysteretic damping. The solution of the soil responses was given by differential iterative method combined with MTLAB programming. The model's accuracy was validated against a three-dimensional (3D) finite element model and the Smith model. Sensitivity analysis was performed on parameters such as discreteness, time interval, cone angle, and non-linear stiffness. The model shows advantages in simulating stress wave propagation in pile toe soil under HSDL, with attenuation rates decreasing with depth and wave speeds stabilizing after an initial decrease. The soil elastic modulus, pile diameter, cone angle, and impact loads influence the attenuation rate, while only the elastic modulus significantly affects wave speed. The results could be helpful for the simulation of the pile toe soil under HSDL and the study of the attenuation of stress waves in the soil.