Abstract:
Wave impeding barrier (WIB) were often used to reduce source vibration, but the research on traditional WIB vibration isolation was limited to single-phase elastic or two-phase saturated foundations. While the soil in nature is usually tri-phase unsaturated soil, the propagation characteristics of elastic waves in unsaturated soil media are different from single-phase elastic media or two-phase saturated porous media. Consequently, this study establishes a mathematical model that installing WIB in unsaturated foundation overlying bedrock. Based on the wave theory in unsaturated porous medium and elastic medium, the isolation effect of WIB on P-wave in tri-phase unsaturated foundation is studied; the solutions of surface displacement after installing WIB in an unsaturated foundation under P-wave incidence are obtained according to the Helmholtz principle; and the effect of some key physical and mechanical parameters are analyzed such as incidence angle, incidence frequency, saturation and shear modulus, thickness and burial depth of the WIB on the vibration isolation effect of WIB in the unsaturated foundation. The results showed that saturation has a significant effect on the vibration isolation of the WIB; that the vibration isolation effect of the WIB increases and then decreases with increasing saturation; that its vibration isolation effect decreases and then increases with increasing incidence angle; that the WIB is effective in isolating vibration caused by elevated, but it is limited and narrow for medium- and high-frequency, and there existed a critical thickness; and that the vibration isolation effect of WIB can be enhanced with the increasing burial depth and shear modulus.