Study on the isolation effect of a composite multilayer wave impeding block on the S-wave in an unsaturated foundation

The traditional wave impeding block (WIB) is improved to a composite multilayer WIB with the same thickness (tri-layer as an example). Firstly, a physical model of the composite multilayer WIB installed in an unsaturated foundation is established, and the isolation effect on the S-wave is studied based on the wave theory in unsaturated porous and elastic media. The purpose of this study is to enhance the isolation frequency of WIB and to show the best isolation effect achieved by selecting the appropriate wave impedance ratio. The influence of saturation on its vibration isolation effect is also analyzed.