To provide a tunnel boring machine capable of being easily recovered after a tunnel with a predetermined length is bored while a pipeline is formed.
A large-diameter cutter head capable of wholly excavating ground ahead of an outer shell body 1 is constituted by adding an outer periphery-side spoke body 4b1 to a spoke body 4a1 which constitutes a small-diameter cutter head 4a. The cutter head 4a, which can be removed integrally with a boring machine body A to the side of a starting shaft through the pipeline P, is constituted by removing the spoke body 4b1. After the completion of tunnel boring, the diameter of the cutter head 4 is reduced; guide rollers 6a and 6b are mounted on a back end of an inner shell body 2 of the boring machine body A and a lower peripheral part of the contracted cutter head 4, respectively; and the boring machine body A equipped with the cutter head 4 is recovered and removed by being rolled on the pipeline, while being stably supported by the guide rollers 6a and 6b.
SATO HIROMI
SATO HIDEO
YABUNO KAZUHIRO
