Integrated 3D modeling of train-induced ground vibrations considering track irregularities and wave impeding barrier performance under different subgrade stiffness conditions.

This study developed a three-dimensional (3D) numerical model to simulate the propagation of ground vibrations induced by high-speed trains (HSTs) traversing tracks with irregularities. The dynamic interaction between wheels and rails was first analyzed using a coupled multibody vehicle model integrated with randomly generated track irregularities defined by power spectral density (PSD) functions. The resulting dynamic loads were then incorporated into a validated 3D finite-difference model to simulate vibration propagation and assess mitigation measures. Unlike previous studies that considered vibration generation and mitigation separately, the proposed framework integrates stochastic track irregularities, vehicle-track interaction, and Wave Impeding Barrier (WIB) performance assessment within a single 3D time-domain model. The numerical framework was subsequently applied to evaluate the influence of track irregularity conditions, subgrade soil stiffness, and WIBs on vibration propagation characteristics. The results demonstrate a direct correlation between track unevenness and vibration intensity, with more pronounced irregularities leading to higher vibration levels. Increasing soil stiffness from 5 MPa to 50 MPa reduced vibration amplitudes by approximately 60%. Furthermore, the analysis confirms that a strategically placed WIB is a highly effective countermeasure for reducing ground vibrations induced in soft soils. A WIB with sufficient width larger than the wavelength (λ) can achieve isolation efficiency ranging from 50 to 70% up to 20 m from the track, bringing vibration levels closer to human comfort thresholds even under poor track conditions. The proposed framework provides a reliable computational tool for vibration assessment and mitigation in high-speed railway corridors.