A layered inter-domain BE-FE coupling method for simulation of wavefield transmission in stratified media

Surficial ground-borne vibrations, which are typically dominated by Rayleigh waves, propagate through near-surface geological profiles that often consist of multiple layers with arbitrary geometry and contrasting properties. Complex phenomena, such as reflection, refraction and scattering of the waves may occur, resulting in persistent motions at the surface. Accurate numerical modelling of these effects is important for both small-scale soil-structure interaction and large-scale site-city interaction studies, where the interplay between near-surface layers, foundations, and structures must be considered with high fidelity and computational efficiency. Most existing boundary-element-finite-element (BE-FE) coupling schemes are restricted to a single-layer interface between the BE and FE subdomains, which limit their flexibility in modelling multi-layered or multi-domain configurations. To address this challenge, we develop a generalized hybrid BE-FE algorithm capable of solving layered inter-domain interface. The proposed approach satisfies elastodynamic continuity conditions along all interfaces, thereby enabling stable and accurate transmission of wavefields between the adjacent domains. Verification of the solution is presented through comparison with numerical benchmarks. A case study involving wave barriers embedded within a layered subsurface is presented to demonstrate its practical relevance. The attenuation effect and mitigation performance of such a system against ground-borne vibrations are discussed.