| 摘要 |
PROBLEM TO BE SOLVED: To provide a shield machine enhancing reliability of protective bits even in such construction work that long excavation and high strength walls appear numerously. SOLUTION: The shield machine 1 has a plurality of protective bits 5 provided at the outer peripheral part of a shield frame 2 at spaces in the axial direction of the shield frame 2 and located in front of a protrusion 4 projected from the shield frame 2, to protect the protrusion 4. The protective bits 5 are composed of main bits 6 and lower and wider subbits 7 than the main bits 6. COPYRIGHT: (C)2010,JPO&INPIT |
