Abstract: To address the issue of excessive noise in high-speed railway vibration signals acquired from the surface of shallowly buried tunnels, a high-order local maximum synchrosqueezing transform (HLMSST) method is introduced for noise reduction in high-speed railway vibration signals traversing shallow tunnels. Firstly, a high-order modulation operator is introduced to calculate the instantaneous frequency for high-order estimation. Subsequently, a HLMSST is developed by integrating the local maximum synchrosqueezing transform. Its anti-noise performance is validated through numerical simulation using a multicomponent noise signal. Next, the vibration signal from high-speed railway is analyzed using correlation time-frequency analysis to confirm the noise reduction and applicability of the HLMSST. Finally, the time-frequency and attenuation characteristics of high-speed railway vibration signals are analyzed using the correlation time-frequency analysis method. The study can provide a time-frequency analysis method that offers high spectral accuracy and effective noise reduction for vibration signals from high-speed railways in tunnel environments. It further establishes a theoretical foundation for investigating the environmental impacts of such vibrations.

Key words: high-speed railway vibration signal, high-order local maximum sychrosqueezing transform, time-frequency analysis, noise reduction effect, attenuation characteristics