Lateral Dynamic Impedances of Pile Embedded in Saturated Soil Considering Local Debonding at the Pile–Soil Interface

An analytical solution based on the infinite layer theory of Novak and Biot's consolidation equation is developed in this study to evaluate the impact of local debonding occurring at the pile–soil interface. The potential functions are employed to decouple the differential equations that govern the soil deformations, while the dynamic resistances of soil are determined from the boundary conditions at the pile–soil interface in accordance with computational theory for mixed boundary problems. The Adomian decomposition method is introduced to obtain the dynamic impedances of pile. The effects of local debonding on the dynamic resistances of soil are investigated by comparing the results from the present solution with available schemes based on perfect contact assumption. The influences of pile–soil modulus ratio, exciting frequency, soil permeability, and slenderness ratio of pile while considering local debonding were then examined. The numerical results indicate that the local debonding occurring at the pile–soil interface dramatically weakened the lateral dynamic impedances of pile, and this trend was particularly pronounced at high frequency and small modulus ratio. Additionally, the local debonding phenomenon also imposes limitations on the implementation of the equivalent single-phase solution in practical engineering applications. The presented solution theoretically demonstrates the significant impact of local debonding on the dynamic response of piles embedded in saturated soil and may provide insight into determining parameter values in empirical equations.