- 期刊
河床質粒徑分布特性之探討
Research on Features Particle Size Distribution of River-Bed Material
摘要
為尋求構造物在堆積河床上之穩定性，須先對河床堆積泥砂之級配含量作充分之瞭解；並配合水文、地文等分析資料，加以研判，供設計構造物之依據。欲瞭解堆積泥砂中級配之各別粒徑含量，應從河床質採樣着手；經由问床質之採樣分析，可算出各樣品粒徑別之停留百分率及通過百分率，並繪出其粒徑分析曲線，則各樣品之河床質含量，便淸晰地顯露。本文利用容積採樣作質粒徑分析，經分析結果獲致下列結論：1.採樣孔位置不同，其河床質粒徑分析結果亦異；惟在同一座已淤滿防砂埧上游之樣間距離小於100公尺河床平坦者，其粒徑累積含量差異不大；而在埧下游之流心側堆積處，粗顆粒（15公分以上）者差異顯著（9.8%以上）；其堆積處粗顆粒含量較流心處爲多。二，集水區中上游河床表面河床質粗顆粒含量較其次層爲多，致形成阿床表面粗粒化。三，在集水區中游已淤滿防砂埧附近，中礫石（9.5-75MM）含量不大（約8.76%且9.5 MM以上之中粗礫石含量佔61-71％間細礫石佔7-11％，此爲本省東北部中游集水區築埧淤滿後河床堆積泥砂所具有的特徵。
關鍵字
無資料並列摘要
In order to search for the stability of the construction built on the alluvial river-bed in watersheds, we mist find the sediment content and its particle size distribution. in addition the analytical data of hydrology and physiography are also important for the design of the constructions. This paper is to analyze the particle size distribution of river-bed material using bank sampling method. Fromdata obtained, we can draw following conclusions: 1. Particle size distribution of the river-bed material varies with the sampling sites. However, in the upstream of mild slop river-bed there is little difference in particle distribution within 100 m distance on the full-sedi-mented sabo-dam. Only the particles larger than 15 cm are higher on the streamline sides than in the streamline for downstream location of the dam. 2. The contents of large particle sizas are higher in the surface river-bed material than those in the subsurface for mid-and upstream of the watershed. 3. In the area of midstream in the watershed, the content of medium gravels (9.5-75 mm) is about the for the full-sedimented dan. The content of grasvels larger than 9.5 mm range between 61% and 71%, and that of fine gravela (2- 4.8 mm) ranges between 7% and 11%. These particle size distrubu-tions are features of river-bed cumulated sediments of the full-sedimented sabo-dam in the midstream of Northeastern watershed in Taiwan.