Prediction of Underground High-Tech Laboratory Vibration Induced by a Freight Wagon: On-Site Experiment and Validation of a 3D Numerical Model

The high efficiency and large volume of freight railways facilitate the movement of cargo; however, they might bring environmental vibration problems, especially during the planning and design of a high-tech laboratory. In this paper, a dynamic testing device and technology that are suitable for underground vibration tests were developed and effectively applied, and the statistical analysis of the environmental vibration at a freight railway line has been carried out, in which the characteristics and attenuation laws of ground and underground vibration are analyzed. Simultaneously, a vertical freight wagon-ballasted track–soil numerical analysis model was established based on vehicle–track coupled dynamics and the Green’s function method (GFM), which was validated by field test results. Based on this, the vibration levels of the high-tech laboratory are assessed according to the relevant evaluation indexes and control standard, and the effect of an isolation trench on restraining the freight wagon-induced vibration has been investigated. The results show that the low-frequency components play a dominant role in the freight wagon-induced vibration. The magnitude of the underground vibration is inversely correlated with the depth and positively correlated with the train speed, and the maximum vertical acceleration increases approximately 1–2 mm/s2 for every 10 km/h increase in the train speed. In addition, the isolation trench effectively weakens the propagation of the ground vibration and plays a positive role in the barrier of medium–high frequency components above 31.5 Hz. The results could provide a testing device and a method for studying the characteristics of underground vibration, and provide the model basis and research ideas for the vibration isolation design of underground structures in the propagation path.