Numerical and experimental study on effectiveness of multi-layered foundation in mitigation of railway-induced vibrations

This paper investigates the effectiveness of layered foundation systems in mitigating railway-induced vibrations using a Finite Element/Infinite Element (FE/IE) model and a scaled-down laboratory model. Traditional single-layer isolators often face bearing capacity limitations, prompting the use of layered under-foundation isolators (LUFI) as a practical alternative. Five different isolator configurations, including single-layer (SUFI) and multi-layer (LUFI) setups, were assessed under varying soil conditions and building characteristics. The study employed a parametric analysis to evaluate vibration reduction performance, measured by the Insertion Loss (IL) index. Results indicate that single-layer isolators generally outperform multilayer isolators of equivalent total thickness, particularly in stiffer soil conditions. However, when the rubber thickness is increased proportionally across multiple layers, multi-layer isolators demonstrate superior vibration attenuation. The effectiveness of the proposed isolation method in a real-world situation was then confirmed by developing a 3D numerical model and a scaled-down laboratory model of a building adjacent to a railway track. The accuracy of the numerical approach was also validated by comparing its results with those from the laboratory model. The study underscores the importance of considering soil-structure interaction, isolation frequency, and isolation layers in the design of effective vibration mitigation systems.