| 摘要 |
PROBLEM TO BE SOLVED: To provide a shield device for use in culvert backfilling, which excavates and removes the earth on the periphery of an existing culvert while reducing excessive excavation of the ground and minimizing frictional resistance. SOLUTION: The shield device includes a shield body 1 having a skin plate 2 which sheathes a peripheral portion of the existing culvert C, and the skin plate 2 is formed of a double structure consisting of an inner peripheral plate 21 slidably sheathing the existing culvert C via a sealing member 24 in an axial direction, and an outer peripheral plate 22 sheathing the inner peripheral plate 21 with an accommodating space 23 interposed therebetween. Then, a plurality of excavating bits 26 are arranged at a front portion of the skin plate 2, and a cutter drive unit 28 for circumferentially driving the excavating bits 26 is arranged in the shield body 1. Further, a driving plate 27 for transmitting power to the excavating bits 26 is disposed in the accommodating space 23.
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