| 摘要 |
PROBLEM TO BE SOLVED: To prevent an excavator body of a tunnel excavator from being easily retracted in order to enhance the working efficiency of excavation. SOLUTION: A cutter head 17 is mounted in the front part of an excavator body 11 so that it can be rotated by a cutter turning motor 20. Supports 12, 13, 14 for pressing the excavator body 11 against the inner wall surface of an existing tunnel so as no positionally hold the excavator body 11 are provided in the excavator body 11. Next, a rear grip 26 is arranged in rear of the excavator body 11, and is made into press contact with the inner wall surface of the existing tunnel so as to be positionally held in order to receive a reaction force of excavation. A thrust jack 30 is laid between the excavator body 11 and the rear grip 26, and a retraction preventing mechanism 42 is coupled to the rear part of the excavator body 11, as viewed in the excavating direction, through she intermediary of a towing tool 41. |
