| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to smooth convey also gravel having large particle size mixed with sedimentary sand through the inside of a scour pipe when a siphon scour method for reducing energy and cost necessary for scour work is adopted and to enable surely the execution of the scour work capable of corresponding also to the sedimentary sand mixed with gravel. SOLUTION: A method for scouring sedimentary sand in a dam reservoir 5 is so constituted that a suction pipe 3 of one end of a scour pipe 1 used as the bottom is opened to the bottom of a lake of the dam reservoir 5, a discharge pipe 4 of the other end is opened to a diversion channel 6 in the downstream and that water and sedimentary sand 18 in the dam reservoir 5 are sucked up with sipon operation of the scour pipe 1 and are discharged to the diversion channel 6. In that case, an air inlet is provided to the scour pipe 1, a high speed rotational flow is generated inside of the pipe by air blown out along the circumferential wall in the pipe of the scour pipe 1, an air core is formed in the center of the scour pipe 1, and a rotational flow of earth and sand is formed in the circumference.
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