| 摘要 |
PROBLEM TO BE SOLVED: To press grippers to the inner wall surface of bedrock, and to partially prevent falling-in of the bedrock by installing plural elastic bodies in parallel in a respectively replaceable state on the surfaces of the respective grippers contacting with the inner wall surface of the bedrock. SOLUTION: Elastic bodies 11 are arranged on the surfaces of two or more grippers 3 to expand the total area contacting with the tunnel inner wall surface T so as to fix the rear part of a boring machine 1 by proper pressurization of a jack 3a. In this case, in order to provide the grippers 3 with the elastic bodies 11 in the rear part of the boring machine 1, the gripper are fixed in the respective directions such as the longitudinal direction and the rotational direction to excavating reaction of a front cutter head. The elastic bodies 11 are arranged in a plurality on the surfaces of the grippers 3, and even when a partial elastic body 11 is damaged by being installed by a bolt, a function of the grippers 3 can be inexpensively and easily restored. Therefore, the contact area between the grippers 3 and the inner wall surface T of beadrock is expanded to reduce contact pressure between both so as to prevent falling-in of the inner wall surface T. |
