| 摘要 |
PROBLEM TO BE SOLVED: To provide a branch shield pipe-jacking method in which branch track tunnels can be branched from a plurality of positions of a main-track tunnel and branch-track shield machines can be branched and started to both left and right sides and the increase of machine length is inhibited and curved propulsion performance is ensured and structure can be simplified. SOLUTION: Fixing onto a shield machine body 4 of an internal drum member 5 is released and a rear end section is connected to a segment Sa, a shield machine 1 is forwarded and moved to the internal drum member 5, and a special segment is constructed near the internal surface of the internal drum member 5 and branch starting shafts under a sealed state are formed of a new raw material concrete at both left-right end sections. The internal drum member 5 is forwarded and moved to sections other than the internal drum member 5 by a shield jack 23 and superposed on a drum member 3, one branch starting shaft under the sealed state is branched and started while being excavated by a branch-track shield machine, and the other branch starting shaft under the sealed state is branched and started while being excavated by the branch- track shield machine.
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