| 摘要 |
PURPOSE: To eliminate subsidiary methods such as ground freezing, chemical grouting, etc., enable the execution of cut-off work in a tunnel joint with a mechanical construction and to make it possible to simplify the construction of a shield machine in comparison with a previously applied shield machine. CONSTITUTION: A cutter disc 32 of a small diameter shield machine 3 and a cutter chamber 33 including a rotary driving device 36 thereof are arranged in a vertical direction along a skinplate 31a through a slide jack 37 in a slidable manner. An outside diameter of a cutter disc main body 13 equipped with an over cutter 14 of a large diameter shield machine 1 is slightly smaller than an inside diameter of the skinplate 31a. A joint ring 22 is projected forward to a bulk head 18 of the large diameter shield machine 1, and a cutter disc 12 is capable of moving to a large diameter shield machine main body 11 so that a rotational center position of the cutter disc 32 corresponds with the rotational center position of the cutter disc 32. |
