Vibration Isolation of Plane Waves by Periodic Pipe Pile Barriers in Saturated Soil

Pile barriers as an effective method for isolating ambient vibration have been used in practical engineering for many decades. However, the study of multiple rows of pile barriers in saturated soil is rare, especially of periodic pipe pile barriers in saturated soil. Based on a new method called the COMSOL partial differential equation (PDE) method, this paper investigates the vibration isolation of plane waves by periodic pipe pile barriers in saturated soil. First, through some comparisons with results from related works, the COMSOL PDE method is validated. Second, the first complete attenuation zone (CAZ) of pipe piles embedded periodically in saturated soil is studied; the effects of parameters such as the filling fraction, arrangement configuration, and filling materials on the first CAZ are discussed. Two kinds of formation mechanism of the first CAZ for periodic filled pipe pile barriers, the Bragg scattering mode and the locally resonant mode, are investigated comprehensively. Both two-dimensional (2D) and three-dimensional (3D) models with multiple rows of periodic pipe piles in saturated soil are built, and the displacement responses behind the pile barriers are analyzed in the frequency domain. This study provides a sound background for the application of periodic pipe pile barriers in saturated soil to isolate ambient vibration in engineering practice.