| 摘要 |
PROBLEM TO BE SOLVED: To allow common use of a shield machine main body, having a plurality of propelling jacks mounted thereon, in a case where two or mote tunnels are constructed from the same starting shaft while no arrival shaft being constructed, or in a case where tunnels are constructed at completely different locations, to thereby suppress the construction cost of the shield machine. SOLUTION: There is provided a shield machine 1, which is comprised of a shield machine main body (internal cylinder machine 2), an external cylinder 3A mounted separably on the front end of the main body, and a plurality of propelling jacks 14A, 14B attached to the shield machine main body and the external cylinder, respectively. A tunnel is constructed from a starting shaft using the shield machine 1. Thereafter, the shield machine body, separated from the external cylinder, is returned to the starting shaft, whereby the main body is diverted to new tunnel construction. |
