Numerical Analysis of Factors Affecting Ground Vibrations due to Continuous Impact Pile Driving

In this study, axisymmetric numerical modeling of continuous impact pile driving from the ground surface to the final depth of pile installation was successfully conducted using arbitrary Lagrangian-Eulerian (ALE) adaptive mesh method. To verify the generated ground vibrations remarkably better with field data compared to previous numerical models, the pile-soil interaction was significantly improved, and all prevalent simplified assumptions were ignored as well. Then, the variation of PPV, the maximum experienced velocity of a soil particle known as peak particle velocity, in different ground depths was meticulously investigated, and it was concluded that PPV can occur in ground depths rather than the ground surface after a threshold radial distance from the pile centerline. The PPV at radial distances more than 8 m and depth of 1 m was between 5 and 15% greater than the values recorded at the ground surface. Moreover, critical depth of vibration was investigated, and it was observed that penetration of a pile up to more than its half-length guarantees PPV occurrence at all radial distances. Finally, a series of extensive parametric studies were carried out in which hammer impact force, pile diameter, tip angle, and damping ratio of soil were concluded as the factors most affecting the ground vibrations induced by impact pile driving.