为能够准确预测全断面隧道掘进机（TBM）刀盘筋板焊接区域的疲劳寿命，以疲劳累积损伤为理论基础，采用缺口应力法对焊接区域进行疲劳寿命研究。首先，在误差允许范围内对刀盘进行简化建模，简单分析刀盘工况，并编程简化获得外部激励载荷；其次，分析缺口应力法在刀盘焊接结构上的适应性，对刀盘整体进行瞬态动力学仿真确定危险区域为筋板位置，采用虚拟缺口半径法建立TBM刀盘筋板模型，从而更好地体现焊缝处的细节特征，随后进行子模型仿真分析，将结果中焊根处的应力作为疲劳评估的参考应力；最后，基于修正的S-N曲线结合修正的平均应力保守估算焊接结构的寿命。结果显示： 1）采用缺口应力法可以精确预测刀盘的疲劳寿命，筋板的疲劳寿命在其焊根处最小N=2.326×107，经计算刀盘掘进距离约为21.9 km时，焊缝处将率先发生疲劳破坏，所得计算结果与实际情况相近； 2）TBM在掘进过程中刀盘焊接区域容易出现不同程度的疲劳损伤，导致TBM提前失去工作能力，造成工程上大量不必要的损失，研究刀盘焊接疲劳寿命对工程施工及结构改进具有重要的意义。

To accurately predict the fatigue and service life of the welded area of the fullface tunnel boring machine (TBM) cutterhead, the notch stress method is adopted to study the fatigue and service life of the welded area based on fatigue cumulative damage. First, a simplified model is established for the cutterhead within the allowable range of error, the cutterhead working conditions is analyzed briefly, and the external excitation loads is obtained by programming. Second, the adaptability of the notch stress method on the cutterhead welding structure is analyzed, the transient dynamics simulation is performed on the entire cutterhead to obtain the dangerous area (rib). Moreover, the virtual notch radius method is used to establish a TBM cutterhead rib model to better reflect the detailed characteristics of the weld. Then the submodel simulation analysis is performed, and the stress at the weld root in the result is used as the fatigue assessment factor. Finally, the service life of the welded structure is conservatively estimated based on the revised SN curve combined with the revised average stress. The results show the following: (1) The fatigue and service life of the cutterhead can be accurately predicted by the notch stress method. The fatigue and service life of the ribs is at the root of the weld(minimum N=2.326×107). When the cutting distance of the cutterhead is about 21.9 km, the welded joint will take the lead of fatigue failure. The calculated results coincide with the actual situation. (2) During the tunneling process of TBM, the welding area of the cutterhead is prone to different degrees of fatigue failure, causing the TBM to lose its working ability in advance and a large amount of unnecessary losses in the project.