| 摘要 |
PURPOSE:To reduce damage by abrasion to the sand-flash waterway of a dam by stirring and floating sand and gravel damaging the bottom floor of the waterway by a method in which a pair of bypassed waterways are provided and their openings are directed at the symmetrically crossing angle on the upstream side. CONSTITUTION:A bypass gate door 9' and a cut-off gate door 7' are opened, and then a sand flash gate door 5' is opened, whereupon water stored flows out with a vigorous power by its pressure through the sand flash waterway 4 to the outside of the dam. The bypassed flowing water passing through a bypass waterway 10 is more accelerated by a negative pressure produced by the main flowing water passing through the waterway 4 in the side wall part of the waterway 4 and spouts crossly upwards to the main flowing water from the opening part. The jet stream of water from the lower opening of the openings of the paired bypassed waterways blows up sand and gravel flowing down on the bottom floor of the waterway 4, and also the jet stream of water from the upper opening stirs the sand and gravel blown up, whereby diffusing and floating them in the main flowing water. |
