<p>This paper proposes arranging trench-mound wave barrier between the vibration source and buildings to mitigate the impact of human activities on residential environments. Based on porous media theory and continuity equations, a theoretical model of periodic trench-mound barriers for surface wave isolation in unsaturated soils is established. With finite element software, the governing equations describing the dynamic characteristics of periodic barriers in unsaturated soils are programmed in the PDE module. Vibration isolation performance of the periodic trench-mound vibration isolation barrier with defects to the surface wave was analyzed. A single cell of the trench-mound vibration isolation barrier was selected, and the key factors affecting its bandgap characteristics are investigated through numerical simulation. The accuracy of the theoretical model is verified, and the vibration isolation performance of defective periodic trench-mound structures is further discussed. The results indicate that both trench defects and mound defects exert adverse effects on vibration isolation efficiency. In practical engineering, the trench depth is recommended to be set at approximately one wavelength of the surface wave.</p>