Vibration Characteristics of Double-Shield TBM Cutterhead Under Rock–Machine Interaction Excitation

During the tunneling process of a double-shield TBM, vibrations generated by rock–machine interaction can affect its safe, efficient, and stable operation. This study was based on the Eping Water Diversion TBM Project. By deploying a vibration monitoring system, the original vibration signals of the double-shield TBM were acquired. A denoising method combining Improved Complete Ensemble Empirical Mode Decomposition with Adaptive Noise (ICEEMDAN) and Multi-scale Permutation Entropy (MPE) was applied for signals reconstruct. The time-domain and frequency-domain characteristics of the reconstructed signals were extracted, and the three-directional vibration characteristics of the cutterhead were analyzed. The influence of surrounding rock classes and tunneling parameters on the vibration characteristics of the double-shield TBM cutterhead was investigated. The results indicate that cutterhead vibration exhibits anisotropy, with the tangential vibration amplitude being the largest, followed by the axial and radial components. The vibration energy is primarily concentrated in the high-frequency range. As the surrounding rock changes from Class II to Class V, the vibration intensity gradually decreases. During the transition from Class II to Class IV rock, the axial vibration frequency decreases while the tangential vibration frequency increases due to changes in rock-breaking patterns. In Class V rock, lower thrust leads to uneven load distribution at the cutterhead-fragmented rock interface, which increases axial vibration frequency. Meanwhile, lower rotational speed results in smoother cutting and reduces tangential vibration frequency. Increasing cutterhead rotational speed or thrust amplifies vibration intensity. Higher rotational speed shifts vibration energy toward lower frequencies, whereas increased thrust introduces more high-frequency components. The findings of this study provide valuable insights for the structural design, tunneling parameter optimization, geological condition perception, fault diagnosis and prediction of double-shield TBMs, thereby promoting green and intelligent tunneling construction.