Tunnel Boring Machines (TBM) play a pivotal role in the construction of modern tunnels, with their performance directly determining the progress, economic benefits, and safety levels of the construction. As the core component interfacing with the rock, the condition of the TBM cutter significantly impacts the machine's boring performance. Faced with increasingly complex geological conditions, the cutters frequently suffer from abnormal damage, including partial wear, polygon wear, and chipping. Such damages are typically accompanied by reduced rock-breaking ability and increased vibration intensity, leading to severe performance degradation. To propose effective monitoring and maintenance strategies to prevent serious consequences of abnormal damage, such as cutterhead damage or personnel injuries, it is necessary to understand the changes in the operational characteristics of the cutter in such conditions and to accurately assess the specific impacts of abnormal damage on cutter performance. This study uses bench tests and discrete element-dynamics coupled simulations to explore the differences in load-bearing, cutter-rock contact, vibration, and noise characteristics between the normal wear cutter and those with abnormal damages. The results show that abnormal damages affect the cutter's load-bearing and cutter-rock contact properties, thereby increasing the proportion of cutting resistance and reducing energy utilization and rock-breaking efficiency. Additionally, partial wear and polygon wear not only significantly increase the noise/vibration levels of the cutter but also cause the mode of noise and vibration to shift from random to periodic, thus increasing the likelihood of forced vibrations in the system. By combining simulation and experimental results, this study elucidates the mechanisms by which different types of abnormal damage affect cutter performance by altering the motion form and cutter-rock contact mode. The operational characteristics of cutters with abnormal damages, as revealed in this study, in terms of load, vibration, and noise, provide theoretical support for the state monitoring and maintenance strategies of TBM cutters.
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