| 摘要 |
PROBLEM TO BE SOLVED: To provide a method and a device for starting a shield, enable the branched shield to be directly started from a main tunnel without constructing a shaft. SOLUTION: A shield machine (1) is made to advance for excavation by being provided with a cutter having a diameter contracting means enabling the excavation of the main tunnel and the branched pit. When the shield machine (1) arrives at a prescribed branched position of the main tunnel, the diameter of the cutter is contracted, a cutter driving part (7) is retreated and retracted into the shield machine (1), the shutter (4) of the front face is closed, the driving part (7) is rotated toward a branched start direction, the skin plate (17) of the main tunnel shield is pulled out into the pit, and the driving part (7) is started as a branched shield machine.
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