In the case of normal wear, we recommend that the disc cutter needs to be replaced when the cutter ring of gauge cutter is worn out about 10-15mm, and the cutter ring of face cutter and center cutter is worn out about 20-25mm. At this time, the cutting edge of the cutter ring becomes wider and its ability to cut rocks is reduced. The torque and thrust required for TBM tunneling will increase, which increases the load of the TBM hydraulic system and motor system, and the crushed rock will also wear the cutter head, thereby reducing the service life of the TBM.