| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a skill for designing the sand collection gate of a sand sedimentation basin in consideration of movement of deposited sand in a flow of a moderate rate. <P>SOLUTION: In a method for designing the sand collection gate of the sand sedimentation basin, following five processes are carried out; a process for calculating a flowing out coefficient by assuming an opening degree which is a distance between a sand collection gate lower end and a sand sedimentation basin bottom and water depth at an upper stream side than the sand collection gate, a process for specifying the opening degree satisfying a formula of submerged flowing out by applying the assumed opening degree, assumed water depth at the upper stream side, the calculated flowing out coefficient and a contraction coefficient which is a constant to the formula of submerged flowing out, a process for calculating a flow rate and a hydraulic radius at a downstream side than the sand collection gate based on the specified opening degree, a process for calculating friction velocity by applying the calculated flow rate and the calculated hydraulic radius at the downstream side and a predetermined roughness coefficient to a Manning formula and calculating a non-dimensional tractive force based on the friction velocity, particle size and specific gravity of the sand to be removed, and a process for determining whether a sand moving form at the sand collection gate downstream is traction sand or not based on the sand particle size and the calculated non-dimensional tractive force and when the sand moving form is traction sand, the opening degree of the sand collection gate is determined to be the specified opening degree. <P>COPYRIGHT: (C)2012,JPO&INPIT |
