Dynamic Vertical Response of Piles Embedded in Layered Deposits and Its Application to Pile Integrity Testing

Existing analytical approaches are unable to simultaneously satisfy the strong-form continuity conditions for both stress and strain at the soil–pile interface and between adjacent soil layers. This can affect the accurate interpretation of natural frequencies of piles and the results of pile integrity tests (PITs). To overcome this shortage, this paper proposes a novel semianalytical model to address soil strong-form continuity conditions in the analysis of PIT results, as well as the frequency-domain impedance analysis of a single pile embedded in layered soils. The rationality and superiority of the proposed model are verified through comparison with state-of-the-art existing solutions. A parametric study is further conducted to investigate the influence of key factors, including the location, stiffness, and thickness of weak interlayers on the interpretation of PIT, with special emphasis on both the dynamic response and the frequency-domain impedance spectrum of the pile.