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豪雨による貯水池決壊時の洪水土砂流出に関する研究

暴雨溃决水库洪水泥沙径流研究

基本信息

批准号：
62601523
负责人：
村本嘉雄
金额：
$ 1.92万
依托单位：
Kyoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research on Priority Areas
财政年份：
1987
资助国家：
日本
起止时间：
1987 至无数据
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-62601523/
关键词：
貯水池決壊ダム決壊洪水流出土砂流出パイピング段波

项目摘要

本研究では, 貯水池の決壊の形態と過程を既往の災害事例と基礎実験及び水理解析によって研究するとともに, 決壊時の洪水・土砂流出量とその流下過程について固定床・移動床水路実験を行い, その解析から貯水池決壊に伴う洪水土砂流出を予測するための基礎的知見を得た.先ず, 土堰堤を中心に豪雨時の決壊原因を検討した結果, パイピングによる決壊過程に不確定な要素が多く, その機構解明が重要なことが指摘された. ついで, 堤体底面に先端浸透型及び全面浸透型のパイプ状空調が堤体中央と下流法肩位置に発生し, 破壊が進行する場合を想定して, 3種類の均一砂を用いた鉛直二次元の浸透実験を行い, 噴砂現象の発生に注目した破壊過程の区分ならびに過剰間隙水圧が堤体の変形・破壊と浸透流量に及ぼす影響について考察した. また, 有限要素法を用いた浸透解析からパイプの発生による浸潤線・間隙水圧分布・浸透流量の変化を予測し, 浸透流量の増加量とパイピングの進行との関係を明らかにした.つぎに, 貯水池の推砂高・水深・貯水延長・下流端条件を変化させた広範な基礎実験を行い, 洪水・土砂流出のハイドログラフについて水理解析の結果と比較し, その適用限界を明らかにするとともに, 推砂高・水深比の増加に伴う土砂流出機構と流出土砂量に対する支配水理量の変化について考察した. 一方, 洪水・土砂の流下過程については, 固定床及び移動床の急勾配水路を用いて, 水と土砂を含む貯水池の瞬時決壊実験を行い, 段波の伝幡速度と変形過程ならびに河床変動と下流への流出土砂量に注目して検討を行った. その結果, 固定床における段波の変形と逓減が顕著で, 伝幡速度から評価した抵抗係数が定常流の場合の3〜5倍になり, 移動床の場合は波形が急峻で一様進行波に近く, 抵抗係数も2〜3倍増にとどまることが明らかになった.

This study provides basic knowledge on the form and process of reservoir burst, previous disaster cases, foundation and analysis of hydrologic process, flood, soil and sand outflow and downflow process during reservoir burst, fixed bed and moving bed waterway, and prediction of reservoir burst and associated flood, soil and sand outflow. First of all, the cause of the decision when the earth dam is in the center of heavy rain is discussed. The result is that the decision process is uncertain, and the mechanism is important. In addition, the occurrence of sand blasting phenomenon in the bottom of the levee, the differentiation of water pressure in the gap, the shape of the levee, the penetration flow rate and the influence of sand blasting on the occurrence of sand blasting phenomenon are investigated. In addition, the finite element method was used to analyze the infiltration and predict the changes in the infiltration line, gap water pressure distribution, and infiltration flow rate during the formation of the diaphragm, and the relationship between the increase in infiltration flow rate and the progress of the diaphragm operation was clarified. In addition, the sand pushing height, water depth, water storage extension, downstream end conditions of the reservoir are changed, the basic conditions are carried out, the flood, soil and sand outflow are changed, and the results of hydraulic analysis are compared. The applicable limits are changed, and the sand pushing height, water depth ratio, soil and sand outflow mechanism and outflow amount are changed. On the one hand, flood, soil and sand flow process, fixed bed and moving bed emergency water distribution, water and soil and sand storage tank instantaneous resolution, wave speed change process, river bed movement, soil and sand outflow volume, attention to the study. As a result, the wave shape of the fixed bed is changed, the wave speed is changed, the resistance coefficient is 3 ~ 5 times in the case of steady flow, and the wave shape of the moving bed is changed, the resistance coefficient is 2 ~ 3 times in the case of steady flow.