The copy cutter bit is arranged on the edge of the cutter head. During construction, the profiling cuter can be extended and retracted radially from the edge according to the amount and scope of over-excavation. When the shield machine advances, turns or corrects deviation in the curve section,the space required is created by cutting the soil body through the imitation over-excavation to ensure that the shield machine realizes curve advancement, smooth turning and deviation correction under the conditions of less over-excavation and less interference to the surrounding soil body.
