Harnessing Elastic Metasurfaces Composed of In-Filled Pipes for Surface Wave Attenuation in Layered Half-Space

In this work, we further investigate the surface wave attenuation performance of elastic metasurfaces composed of in-filled pipes in a layered half-space, focusing on the dispersion relations and transmission properties. Particularly, both Rayleigh waves and Love waves are considered. The introduction of soil layers will reduce the width of attenuation zones. Additionally, transmission simulations reveal complex propagation patterns for elastic metasurfaces in a layered half-space, including wave reflection, wave resonance, and higher-order wave modes, which will hinder the penetration of converted shear waves into the half-space. In contrast, in reference cases, only surface-shear wave mode conversion is observed. Moreover, the attenuation performance of elastic metasurfaces is also diminished in layered soils in the frequency domain, and a nonuniform displacement distribution behind the elastic metasurface is also found. Last but not least, the feasibility of elastic metasurfaces to train-induced ground-borne vibration mitigation is numerically verified in the time domain. Although the performance of elastic metasurfaces in layered soils is inferior to that in homogeneous soils, they are better than traditional trenches within the main frequency range. Snapshots from the transient simulation clearly show the evolution of wave fields, reinforcing the observed key findings. Due to excellent surface-wave-attenuation performance and ease of realization, these novel elastic metasurfaces hold great potential in ambient vibration mitigation.