Effects of pile rows on vibration reduction in nearly saturated soil

Abstract

This paper presents an analysis about the vibration reduction effects by a barrier in a nearly saturated soil medium. The barrier is assumed to consist in an arbitrary distribution of parallel cylindrical piles embedded in an infinite nearly saturated soil. Based on the equations governing the motion of nearly saturated soil, the complex wave numbers and amplitude ratios between the liquid phase and solid phase are first derived according to the Helmholtz decomposition theorem. With the aid of the Graff’s addition theorem, the unknown multiple complex scattering coefficients by an arbitrary configuration of piles as barriers are determined by taking an advantage of the boundary conditions at pile-soil interfaces and the linear independence of trigonometric functions. Then the corresponding expressions for the nearly saturated soil displacements at both sides of the pile rows can be obtained. The numerical results show that soil saturation degree and permeability exert significant influences on the isolation effectiveness of pile rows, and that the distance between neighboring rows is crucial for the isolation effectiveness. The isolation rules can provide useful guidelines to the design of pile rows as barriers in nearly saturated soil.