Study on structural health monitoring of vertical vibration of ballasted track in high-speed railway

The ballasted track structure of a high-speed railway repeatedly bears the action of vehicle loads, and the vibration energy is gradually diluted and dissipated due to the ballasted bed. It is difficult to monitor the structural health of ballasted track. By embedding sensors into the ballast, a ballast sensor was obtained. It was positioned on the ballasted track to study the structural health monitoring (SHM) under an impact excitation and to verify the Discrete Element Method (DEM)–Multi-body Dynamics (MBD) co-simulation model. Therefore, the SHM of the ballasted track is realized. The results showed that distributed ballast sensors can realize the SHM status of the ballasted track. Under an impact excitation, the peak of the main vibration frequency of the ballast at the sleeper box, sleeper end and ballast shoulder occurred at a frequency of 153 Hz. At twice the frequency, a secondary peak appeared in the ballast vibration amplitude at the sleeper box, while the vibration amplitudes at the sleeper end and ballast shoulder were suppressed. In low-frequency regime, the vibration damping performance of the ballasted bed structure was better than that in high-frequency regime. When the ballasted track structure was excited by high-frequency vibrations, the surface layer of the ballast at the sleeper box tended to splash, which affected the structural health state. Under the moving wheel load, both sides of the ballasted bed form a “cyclone” shape.