Underground-Train Vibration Transmission and Control for Track–Tunnel–Soil–Building Systems

Underground-train-induced building vibration is a noteworthy new environmental problem. Aiming at the train-induced environmental vibration problem in practical engineering, a three-dimensional train–track–tunnel–soil–building coupled dynamic model is established in which the nonlinear wheel–rail interaction, tunnel–soil interaction, layered soil, and soil–building interaction are considered in detail. A test is conducted to validate its effectiveness, and the influences of running trains on tunnel wall, soil, and building are investigated in depth. The vibration-control effect of steel-spring floating-slab track (FST) and rubber-pad FST combined with structural gap on buildings is studied. Results show that the dynamic model and the simulation method employed are effective in predicting environmental vibration. The amplitude of tested tunnel acceleration is within 0.088–0.151 m/s 2 , and the predominant frequency is within 31.5–100 Hz. The maximum vibration level (VL) of tunnel wall in the 1/3 octave domain is 61–80 dB. Running trains indeed excite soil vibration; near the ground surface this is amplified. The predominant frequency of soil vibration is 50–80 Hz; vibrations above 100 Hz are largely absorbed by soil. When waves travel across an interface, refraction and reflection effects make the vibrations more complex. For tall building systems, the vertical total VL (VL zmax ) is concentrated within 48.1–64.3 dB for vertical distribution, and the vibration energy is mainly concentrated at 63 Hz. In this project, the vibration-isolation effect of steel-spring FST is significant, and vibration above 16 Hz is effectively isolated, VL being reduced by 14.6 dB at most.