| 摘要 |
PROBLEM TO BE SOLVED: To provide a tunnel excavator having a cutter head which can directly excavate a sealing wall of a departure shaft and an arrival shaft constructed at tunnel construction irrespective of an obstacle at an excavation destination.SOLUTION: In a tunnel excavator, a cutter head 15 is rotatably supported to a front barrel 11a of an excavator main body 11, a plurality of earth and sand excavation bits 32 and a plurality of obstacle excavation bits 33, 34 and 40 are arranged at a tapered and conically-inclined cutter face of the cutter head, and the obstacle excavation bit 40 is arranged while enlarging an attachment range up to the center of the cutter face. In the center of the cutter face, there are arranged the obstacle excavation bit 40 which is arranged by enlarging the attachment range and a columnar center bit 39 which constitutes a center cutter, and a height of the center bit is set not higher than a face of the highest bit of the obstacle excavation bits arranged by enlarging the attachment range. |
