| 摘要 |
PROBLEM TO BE SOLVED: To provide a cutter head capable of surely and efficiently cutting and removing an obstruction such as sheet piles, piles, etc., existing on a designed tunnel line. SOLUTION: A fixed head section 7, from which an earth excavation bit 31 is projected, and a movable head section 8, from which an obstruction cutting bit 32 freely protruded and retracted to and from the fixed head section 7 is projected, are disposed at the front end of a center shaft 2 while a fixed arm 5 with a plurality of earth excavation bits and a rotating arm 6 with spiral cutting bits for cutting an obstruction are protruded radially from the center shaft 2. The cutting bits 11, 32 of the movable head section 7 and the arm 6 with the spiral cutting bits for cutting the obstruction are normally retracted beforehand from excavation bits 9, 31 and a ground is excavated while cutting bits 11, 32 are projected forward from the excavation bits 9, 31, the obstruction is cut in a drill shaped by the cutting bit 31 of the movable head section 8, and the cut hole is cut to remove earth while being cut and spread by the spiral cutting bits 11 of the rotating arm 6. |
