| 摘要 |
PROBLEM TO BE SOLVED: To provide a shield machine capable of excavating a ground while easily removing an existing obstruction in a course. SOLUTION: In the shield machine 10 having a ring cutter 21 crushing a ground by rotary cutting in a cutter head 11, cutters 30 capable of being projected towards the cutting facing side of a tunnel are installed to parts of the ring cutter 21, and the ring cutter 21 is turned under the state in which the cutters 30 are projected to the cutting face sides, and an underground obstruction placed in front of the cutter head 1 is cut. |
