Vibration Reduction of Phononic-Like Crystal Metaconcrete Track Bed for Underground Railway

Train vibrations can travel through the track, tunnel structure, and surrounding strata as well as into the structure of buildings near tunnels, where they can be radiated as low-frequency vibration waves and noises inside the building. Low-frequency vibration reduction is a major challenge for vibration control technology. Herein, the new phononic-like crystal metaconcrete material was invented to make the track bed for decreasing vibration induced by trains because it can open low-frequency bandgaps to reduce the low-frequency vibration in actual subway engineering. First, the original phononic-like crystal model was optimized to improve the vibration reduction effect for low-frequency bandgaps. Second, the metaconcrete track beds were conducted according to the new phononic-like crystal model based on the vibration reduction need. Finally, the metaconcrete track beds were installed in the Ning-Ju line of Nanjing Metro in Nanjing, China, and the vibration reduction effect was monitored. The monitoring results in the Ning-Ju line demonstrate that the new phononic-like crystal structure metaconcrete track bed has excellent vibration reduction performance for rail transportation.