Abstract:
Objective With the development of vehicle depot overhead properties, the vibration and noise issues in superstructures caused by vehicle operations have significantly increased. The depot superstructures are closely related to the track layout; therefore, quantitative analysis is required for vibration and noise reduction measures regarding the parking lots and access lines of double-deck depots.
Method Taking an overhead parking lot of an operating depot in Shanghai as a case study, the parking lot, access lines, and adjacent buildings are set as the most unfavorable sections for vibration and noise. A vehicle–track–soil–superstructure vibration model and a vehicle–access line–building acoustic model are established and verified, respectively. The track-superstructure vibration and noise characteristics during train operations are analyzed, and suggestions for vibration and noise reduction for the parking lots and access lines are proposed.
Result & Conclusion When trains are operating in both the upper and lower parking lots, if standard fasteners are used for the tracks in the upper parking lot, the maximum Z-weighted vibration level of the superstructure floor slab exceeds the relevant normative limits, with a peak frequency of 400 Hz. Considering the soft soil geology of the area, the vehicle-induced vibration from the lower parking lot contributes little to the superstructure vibration. Adopting vibration-damping fasteners for the upper tracks and standard fasteners for the lower tracks can satisfy the vibration requirements of relevant standards. Applying a fully enclosed sound barrier of a certain length along the access lines can significantly reduce the high-frequency noise transmitted to adjacent buildings. When the sound barrier length exceeds 70 m, the outdoor noise on all floors of the adjacent buildings near the access lines can meet the limit requirements of relevant standards.