Field Monitoring of TBM Vibration During Excavating Changing Stratum: Patterns and Ground Identification

TBM vibration is inevitable during excavation in hard rock or mixed face ground conditions (MFC) and is detrimental to equipment safety and environmental protection. However, the cutting-induced vibration can help clarify the TBM-ground interaction and provide a valuable ground identification approach. In the present investigation, a field measurement of TBM vibration in changing ground conditions was carried out with accelerometers mounted on the TBM bulkhead. The vibration characteristics and patterns under different ground conditions were compared by signal processing, and their relationships to the operating parameters were investigated. The results showed that the TBM dynamic response was highly dependent on geological conditions. In homogeneous soft ground (HSG), the magnitude of vibration was low and stable, while under the MFC, the high frequency and strong vibration occurred. The vibration waveform in the MFC had an apparent periodicity and was consistent with the cutter head rotation speed. In addition, the signal consisted of a series of periodical impulses with intervals, revealing the rock-cutting process. Since the TBM vibration was sensitive to ground changes, it could provide valuable and precise information about the cutting face ground conditions. This investigation of the relationship between the ground and vibration can provide a foundation for vibration-based ground identification, which is a potential application in simultaneously tracking geological conditions during tunneling.