臺灣博碩士論文加值系統

摘要 本研究乃利用一系列室內動床實驗來探討河川主導型河口三角
洲之發展過程。在實驗設計上，考慮以推移載為主作用下之河口三角洲地
形。首先利用三角洲發展之平面照片，縱斷面、橫斷面地形圖及三角洲之
長、寬、高、坡度因子(Sb/Sc)隨時間之變化來描述三角洲之發展過程及
形態特性，並利用形狀因子(Rc/Bm)隨時間之變化將三角洲之發展過程區
分為三個階段，然後分別對各個階段進行分析。在第一階段中，利用流速
分佈特性，推求底床剪應力分佈形狀來探討第一階段三角洲之淤積形態。
其次以三角洲第二階段中之中心軸長度({EMBED Equation |})，最大寬度
之擴張角({EMBED Equation |})，橫斷面寬度(B)及橫斷面中心淤積厚度(
{EMBED Equation |})等三角洲之地形量為特性參數，進行平面形態及橫
斷面形態之幾何相似性分析，由分析結果顯示其分別具有明確之高斯函數
及雙曲函數特性。最後探討第三階段三角洲面上產生自發性(self-
formed)渠流的條件。

The developments of the river delta were studied through
aseries of experiments in this study . To simplify
experimentalconditions,steady water and sediment supply were
considered.Atfirst,an experimental run was used to describe the
developmentof the delta.Then the temporal variation of shape
factor wereemployed to classify the development of delta into
three stages.In the first stage,delta developed mainly in its
length,which caused the shape factory reaching a peak.In the
second stage,delta advanced mainly in its width,which resulted
in the decayof the shape factor.In the third stage,the stream
channel var-iated severely,and the shape factor oscilated.In
three stages,the geometric similarity of the delta was analized
by using three topographic scales. The results of the similarity
analy-sis showed that the plane shape,cross section profiles of
thedelta were able to similated by the Gaussin and hyperbolic
fu-nction,respectively. Finally,the occurance of the stream
chan-nel was also studied and discussed.