| 摘要 |
PROBLEM TO BE SOLVED: To provide a surfacing prevention structure of a buried object capable of being easily applied also to the existing underground buried object by a low costed device without being required for any large scaled work with a very simple structure and preventing the incursion of earth and sand mixed water to the underground buried object other than emergency such as an earthquake or the like. SOLUTION: The surfacing prevention structure of the buried object is so constituted that through-holes 12 and 13 communicating the underground 11 side with the inside of a manhole body 2 are formed in a side wall 2a of the manhole body 2 of a manhole 1 and that lid devices 14 permitting or cutting off the flowing of water between the underground 11 side and the inside 200 are provided in the through holes 12 and 13. The lid devices 14 are equipped with an outer cylinder 20 inserted into the through-holes 12 and 13, a pressure receiving plate 21 having cut-off efficiency and a claw member 22 interlocking the pressure receiving plate 21, and each lid device 14 is so constituted that the claw member 22 is fractured to make it secede from the outer cylinder 20 when the pressure difference between the underground 11 side and the inside 200 is in excess of a constant value, water in the underground 11 side can flow to the inside 200 through the outer cylinder 20 and that the circulation of water between the underground 11 side and the inside 200 can be cut-off by the pressure receiving plate 21 when the pressure difference is less than the constant value. COPYRIGHT: (C)2007,JPO&INPIT
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