| 摘要 |
PROBLEM TO BE SOLVED: To prevent uneven wear of a disc cutter, to carry out switching between an excavation position and a water cut-off position by means of a compact structure, and to safely and easily replace the disc cutter from a cutter head spoke inside for reducing a cost and a construction period. SOLUTION: This cutter head is provided with a disc cutter mounting box 21 having a muck discharging passage 35 and an outside cover 23 and an inside cover 24 pivoted to the disc cutter mounting box 21. In excavation, excavation is carried out while excavated muck and the like is discharged from the muck discharging passage 35. In replacement of the disc cutter 13, water, soil and the like is prevented from flowing into the inside of the cutter head spoke 11 when the outside cover 23 and the inside cover 24 are turned so that water is cut off by means of the outside cover 23 on the cutting face side while the muck discharging passage 35 is closed by means of the inside cover 24, and then, the disc cutter 13 is attached/detached for replacement after a bottom part cover 21a and a retainer 25 are removed. |
