| 摘要 |
PROBLEM TO BE SOLVED: To provide a water cut-off valve device for a drainage hole of a concrete box, capable of coping with level fluctuation of a ground water level. SOLUTION: This water cut-off valve device 11 is attached to the drainage hole 13 provided in a bottom part 20 of a box-shaped handhole 12 buried into the ground, and the water cut-off valve device 11 includes a valve element 17 for discharging water in the handhole 12 into an underground and for deterring the ground water from intruding into the handhole 12. COPYRIGHT: (C)2011,JPO&INPIT
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