A combined seismic metamaterial in layered soils

This paper presents a combined seismic metamaterial model based on the principle of local resonance to effectively shield Rayleigh waves at wide low-frequency bandgap in two-layered soil. In the proposed combined seismic metamaterial model, the unit-cell structure comprises two parts: a partially embedded underground concrete column and a multi-layer composite material structure enclosing the underground portion of the embedded concrete columns. By using the finite element method, the band structure and propagation characteristics of the proposed combined seismic metamaterial model are numerically investigated. Later the concrete column height effect is investigated, such as the combined seismic metamaterial model with positive gradient arrangement, negative gradient arrangement, concave arrangement, and convex arrangement. Then, the El-Centro seismic wave is considered and found that it can be considerably attenuated by the designed combined seismic metamaterial model. Additionally, this work does parameter analysis on items such as concrete density and column height.