Dynamic Response of Poroelastic Soil Adjacent to an Axially Vibrating Pile

Understanding the dynamic behavior of poroelastic soil adjacent to an axially vibrating pile is crucial to the seismic design and vibration reduction of various geotechnical engineering projects; however, few analytical studies exist on this issue to this point. In this study, to obtain the dynamic response of fully saturated soil around and beneath a vibrating pile, the solving scheme of the pile-fictitious soil pile (FSP) coupled model is extended to the pile-porous FSP coupled model and surrounded by multiple poroelastic medium layers with finite thickness. The semianalytical solutions of the pile-porous FSP-saturated soil-coupled vibration system are resolved and verified by existing solutions under different degradation situations. The developed model and the solutions are then employed to investigate the wave propagation mechanism in the fully saturated soil. The results show a certain degree of hysteresis in the fluid phase response during the vibration. As the permeability of the poroelastic material decreases, the hysteresis effect of the fluid phase relative to the solid phase weakens, resulting in an increase in excess pore-fluid pressure and a wider range of influence from the vibration. The conclusions derived from this study can also provide practical guidance for pile testing techniques, such as the parallel seismic (PS) method and low-strain pile integrity test (PIT) onsite.