| 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 plurality of cutter spokes 21 crushing a ground by rotary cutting in a cutter head 11, the cutter spokes 21 are fixed and supported to a center-shaft outer pipe having double-pipe structure while and supporting spokes 32 supporting a cutter 30 with a ring cutter 31 capable of being slid towards the cutting face side of a tunnel are fastened onto a center-shaft inner pipe. An underground obstruction placed in front of the cutter head 11 is cut by the ring cutter 31 by integrally turning the inner pipe and outer pipe of a center shaft while the ring cutter 31 is projected from the cutter spokes 21 to the tunnel cutting-face side. |
