Numerical investigation of soil dynamic response during high-frequency vibratory pile driving in saturated soil

The high-frequency vibratory pile driving has been gradually applied for pile installation in central urban areas. However, its adverse impact on the surrounding environment is still uncertain. This paper develops a refined three-dimensional numerical model based on the hydro-mechanical coupling method to investigate soil dynamic responses produced by high-frequency vibratory pile driving in saturated soil. The soil vibration velocity, pore water pressure, and mean effective stress are analyzed. Additionally, parametric analyses of excitation frequency and excitation force are conducted to examine soil responses under different installation parameters. The results show that the peak particle velocity (PPV) of soil reaches its maximum at the depth of the pile tip, with greater vertical PPV below the ground surface than radial PPV. Pore water pressure around the pile increases significantly, leading to a noticeable reduction in effective stress. The changes in pore water pressure and effective stress decrease as the distance from the pile increases. The parametric analysis results indicate that increasing the excitation frequency can significantly decrease the vertical PPV of soil at the depth of the pile tip and reduce the stress disturbance range in the surrounding soil. The pressing force mainly affects the efficiency of pile sinking, while the centrifugal force primarily affects the stress state evolution of soil around the pile shaft.