| 摘要 |
PROBLEM TO BE SOLVED: To easily and quickly expand a fence, and to easily and securely expand the same even when the flow or tidal current of a river is fast. SOLUTION: One end of a flexible fence body 1 having a buoyancy member 2 or a bag body having gas sealed therein is fixed to a riverbank. An expandable rope 4 connected to the other end of the fence body 1 is set beforehand on a subaqueous bottom of a river from the riverbank to which the fence is fixed to the opposite riverbank. Further, the rope is connected to a winding apparatus 6 which is set on the opposite riverbank. When the winding apparatus 6 is activated, the fence 1 is expanded to the opposite riverbank.
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