| 摘要 |
PROBLEM TO BE SOLVED: To provide a starting method for a branch shield using an articulation mechanism, which enables an earth pressure load to be borne by a simple operation. SOLUTION: In an existing tunnel 1, a cutter 3 of the branch shield 2 and a front barrel section 4 are assembled, and a starting port entrance 6 is mounted. The cutter 3 is started to the outside of the existing tunnel 1 from a starting pit mouth 5 by the propulsion of a pipe-jacking jack 18 of the front barrel section 4, and a back end of the front barrel section 4 is started until it is positioned near the back end of the entrance 6. After that, a load bearing member 25 for axially supporting the front barrel section 4 by locking it from the rear is mounted at the back end of the entrance 6. Subsequently, the pipe-jacking jack 18 is retracted, and the branch shield 2 is started after a rear barrel section 33 is assembled in the rear of the front barrel section 4. COPYRIGHT: (C)2006,JPO&NCIPI
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