Impact Analysis of Steel Spring Vibration Isolator Failure in Metro Line Curved Sections on Train Operation Safety

[Objective] In the small-radius curved sections of floating slab tracks, trains and tracks exhibit more complex dynamic response characteristics. The steel spring vibration isolators in the floating slab track system not only play a role in vibration reduction but are also crucial for ensuring the safe operation of trains. Therefore, it is necessary to study thoroughly the impact of the local failure of steel spring vibration isolators on the prefabricated floating slab track structure in small-radius curved section and the operation safety of trains. [Method] Taking the prefabricated floating slab track of a certain metro line as an example, the ABAQUS finite element software is used to establish a coupled vehicle, floating slab track and tunnel dynamic model, and the validity of the model is verified through measured data. According to the established model, the dynamic responses of the train and the track structure before and after the vibration isolator failure are calculated, and the changes in the track structure and the indicators of train operation safety are analyzed. In addition, the impact of the vibration isolator failure on the force condition of the shear hinges is discussed, and their strength is checked and adjusted. [Result & Conclusion] Although the wheel load reduction rate and the derailment coefficient have increased, they meet the requirements of relevant specifications, indicating that the train can still maintain operation safety when the vibration isolators fail. The failure of the vibration isolators leads to a decrease in the track stiffness, resulting in a significant increase in the dynamic displacement of the track structure, which exceeds the limits specified in relevant specifications. Since the force on the upper-mounted shear hinge will increase significantly after the vibration isolators failure, despite meeting the strength requirements, it is still necessary to strengthen the monitoring of the shear hinge.