TB880E型隧道掘进机(TBM)主轴承耐磨钢带被唇形密封磨穿，断裂后刺穿密封，造成密封系统失效，导致大量粉尘等颗粒杂质进入主轴承，需对主轴承密封系统进行修复，在洞内脱离刀盘、解体主轴承密封、更换主轴承唇形密封和耐磨钢带以及修复迷宫密封。实践证明，即使在空间有限的情况下，通过优化传统修复工艺，针对具体问题提出创新修复工艺是能够高效、快速地完成修复工作，可为类似故障提供参考。

The steel strip of the main bearing of TB880E tunnel boring machine (TBM) is worn out by the lip seal. Then the steel strip breaks and pierces the seal, which results in the failure of the seal system. Under such circumstance, a large amount of dusts and other particles enter the main bearing. Therefore, the seal system of the main bearing needs to be repaired. The cutter head of the TBM is dismantled in the tunnel, the seal of the main bearing is removed, the lip seal and the wearresistant steel strip of the main bearing are replaced and the labyrinth seal is repaired. The practice demonstrates that that, even in confined space, the repairing of the seal system of the main bearing can be fulfilled efficiently by optimizing the traditional repairing techniques and adopting innovative repairing process. 