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標題: | 二維水理輸砂模式於壩體移除分析應用之探討 The Application of Two Dimensional Hydraulic and Sediment Transport Modelling in Dam Removal Simulations |
作者: | Wen-Shien Lee 李文獻 |
指導教授: | 李鴻源 |
關鍵字: | 潰壩,拆壩,CCHE2D,NETSTARS,二維水理輸砂模擬,彎道二次流,溯源沖刷,棲地適合度, Dam break,Dam removal,CCHE2D,NETSTARS,Two-dimensional hydraulic and sediment transport simulation,secondary flow,knickpoint mitigation,habitat fitness, |
出版年 : | 2012 |
學位: | 碩士 |
摘要: | 國內通常都是以一維水理棲地模式來模擬河川棲地,然而一維模式僅僅能夠應用於空間大尺度上的河川棲地變遷研究,對於小尺度上的河川棲地複雜行為則較不容易得到一些可靠的結果。本文的研究目的為利用美國密西西比大學之國家水科學及工程中心(NCCHE)發展之CCHE2D水理輸砂模式模擬巴陵壩潰壩案例與七家灣溪一號壩拆壩案例,探討二維 CCHE2D與一維NETSTARS模式的水理及輸砂演算結果並討論潰壩過程中溯源沖刷行為、彎道二次流、上下游底質粒徑變化、水躍現象、河道橫斷面的沖淤變化和Doyle所提出的前三階段是否吻合,最後建立出二維生態適合度圖型探討不同重現期流量下之棲地適合度變化。
研究結果顯示溯源沖刷行為之發展為由一個點而非一個面發展,而彎道二次流發生處之棲地適合度指數明顯比無二次流發生處要高。此外上下游底質粒徑於潰壩後隨著彎道主流方向與於凸岸處產生粒徑細化;而凹岸處則產生粒徑粗化的現象且根據河道凹岸或是凸岸而有不同程度粗化的現象。而潰壩後之上游斷面變化尚符合Doyle(2002)前兩個階段之假設,然第三階段由於Doyle尚未考慮彎道與底床質組成之影響,因此斷面之沖淤行為於橫斷面上之分佈並非均勻,而是根據斷面距離壩體之距離與彎道位置之主深槽流向而呈現斷面上非均勻之沖淤現象。另外,七家灣溪由於受人為干擾、資料量測缺乏、模式設置上之限制與邊界條件上之影響而無法利用二維模式模擬出實測資料之斷面變化情形。 The decision of dam removal need to carefully evaluate of the response of river from many perspectives.Among different issues of dam removal,one of the most challenging and critical concern is how to accommodate or offset the potential short-term impacts associated with the release of stored sediment.Utilizing one-dimensional hydraulic and sediment transport model to simulate the response after dam removal is common and widely accepted .However,it is highly limited in the model assumption and capacity and not able to provide a comprehensive analysis of channel evolution.For this concern,this study makes effort to evaluate to possibility of application of two-dimensional hydraulic and sediment model in dam removal simulations.This study applies a two dimensional model,CCHE2D,and take Barlin Dam Break and the removal of Qijiawan River Dam as case study.By comparing the simulation result from CCHE2D and NETSTARS,another one-dimensional model,this study pays attention to investigate the model capacity to describe two-dimensional hydraulic and sediment transport characteristics such as head cutting and knickpoint mitigration,secondary current flow,and channelization in different in different river section.In addition,two-dimensional Habitat Suitability Index(HSI) map is construced according to the model result and used to discuss the change of habitats under different discharge. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/64691 |
全文授權: | 有償授權 |
顯示於系所單位: | 土木工程學系 |
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