Vibration Reduction of Plane Waves Using Periodic In-Filled Pile Barriers

The frequency dispersion characteristics of pile barriers are receiving more attention due to their effectiveness and a better understanding of their behavior at attenuating middle and lower frequency ground vibrations. Based on a comprehensive study, this paper proposes a two-dimensional periodic pile barrier system, which can produce low-frequency or middle-frequency attenuation zones (AZs). Periodic pile barriers are composed of periodically arranged hollow piles filled with either soft or hard in-fill materials. Finite element method and plane wave expansion method are first used to study dispersion curves, AZs, and corresponding wave dispersion mechanisms. Influencing factors of the periodic pile barrier on the AZs are then identified based on a parametric study. To further illustrate the effectiveness of the vibration attenuation, a three-dimensional pile-soil finite element model with combined periodic pile barriers is analyzed, and the frequency ranges of vibration reduction are found to be consistent with the AZs of the corresponding dispersion curves. The present numerical results are in agreement with existing experimental and numerical results, which validate the existence of AZs in periodic pile barriers. This study provides a new insight into the analysis and design of pile barriers to block vibrations, especially in the low-frequency range. (C) 2015 American Society of Civil Engineers.