- 期刊
切口式防砂壩對土石流之攔擋效率
Effect of Sabo Dam with A Rectangular Slit on Block Debris Flow
摘要
本研究就矩形切口式防砂壩在防治土石流災害上的各項性能進行廣泛地探討及研究，不僅建立了切口式防砂壩泥砂體積濃度折減效率及貯砂效率之表達式，並經實測資料分析獲得土石流經壩體攔擋後之泥砂體積濃度折減效率，與相對開口寬度，渠槽寬度比和流動勢能比等因子有關。研究證實，泥砂體積濃度折減效率及貯砂效率均隨著相對開口寬度之增加而降低，且當試體粒徑組成越均匀，其泥砂體積濃度折減效率越高。而隨著流動勢能比之降低，壩體攔擋之泥砂體積濃度折減效率及貯砂效率越高。泥砂體積濃度折減效率及貯砂效率均隨著渠槽寬度比之增加而逐漸上升。另可獲得壩體上游淤砂水力排砂之臨界相對開口寬度爲b/d_(max)|c≈2.0式中b：切口式防砂壩開口寬度；d_(max)：土石流內部泥砂顆粒之最大粒徑。
並列摘要
The main purpose of this research is to analyze the valuable properties of sabo dam with a rectangular slit. By improving those properties, the dam has more abilities to prevent or reduce the damage caused by block debris flow. Fist, create a mathematical simulation of sabo dam with a rectangular slit on block debris flow by formulating the equation of reduction efficiency of solid volume concentration and trap efficiency. Second, compare these simulation resulting with the actual experimental data, the reduction efficiency of solid volume concentration by block debris flow is conducted on the contributing factors, such as the ratio of relative opening width, the ratio of channel width, and the ratio of potential energy. It can be proved that: The less reduction efficiency of solid volume concentration and trap efficiency are, the more ratio of relative opening width is. The more even grain size is, the higher reduction efficiency of solid volume concentration is. The more reduction efficiency of solid volume concentration and trap efficiency are, the less ratio of potential energy is. The more reduction efficiency of solid volume concentration and trap efficiency are, the more ratio of channel width is. Then, the critical relative opening width of hydraulic de-sand can be obtained as b/d_(max)|c≈2.0 b: the opening width of sabo dam with a rectangular slit; d_(max): the maximum grain size of debris flow。