CREASED-TYPE TUNNEL BORING MACHINE AND WITHDRAWAL METHOD THEREFOR

摘要

PROBLEM TO BE SOLVED: To prevent the production rate of an excavation muck from being excessive, and execute woke for curved line parts of a small radius of curvature. SOLUTION: The shield frame 10 is divided into a front drum part 11 situated at the excavation side and a rear drum part 12 situated at the tunnel side, and the front drum part 11 and rear drum part 12 are joined in a bending manner with each other, herein, the front drum part 11 includes a substantially cylindrical inner shell frame 14 having a cutter frame 13 attached at the side of a natural ground and an outer shell frame 15 being located in divided relation in the peripheral direction at a predetermined distance at the outside part of the inner shell frame 14 for encircling this. The outer shell frame 15 is secured via a connection mechanism 16 to move to and away from the inner shell frame 14.