Propagation Characteristics of Railway-Induced Ground Vibration in Different Soil Conditions and Vibration Isolation Performance of Infilled Trenches

With the rapid expansion of urban rail transit networks, ground vibrations induced by train operations have attracted increasing attention due to their environmental impacts. In this study, a numerical simulation approach was employed to systematically investigate the propagation characteristics of railway-induced ground vibrations under different soil conditions and to evaluate the vibration isolation performance of in-filled trenches. The results indicate that vibration amplitudes exhibit an oscillatory attenuation pattern during propagation. A pronounced vibration amplification zone dominated by Rayleigh waves is observed on the ground surface. This phenomenon can be attributed to the phase differences among P waves, S waves, and Rayleigh waves with different frequency components, which arise from their distinct wave numbers and subsequently lead to constructive and destructive wave interference. As the elastic modulus of the soil increases, the overall vibration response decreases, while the proportion of high-frequency vibration components gradually increases. Regarding vibration mitigation measures, the vibration isolation performance of trenches filled with expanded polystyrene foam and concrete was comparatively investigated. The results demonstrate that the flexible EPS-filled trench provides significantly better vibration isolation than the rigid concrete-filled trench. Increasing the trench depth further improves the isolation performance of the flexible trench, whereas increasing the depth of the concrete-filled trench produces little improvement and may even amplify vibration responses behind the trench. The findings of this study provide a theoretical basis for predicting railway-induced environmental vibrations and optimizing the design of wave-path vibration isolation measures.