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| 題 名 | 橋墩對河川水流的影響 |
|---|---|
| 作 者 | 許銘熙; 李明旭; | 書刊名 | 農業工程學報 |
| 卷 期 | 37:4 1991.12[民80.12] |
| 頁 次 | 頁11-24 |
| 分類號 | 443.046 |
| 關鍵詞 | 水流; 河川; 橋墩; |
| 語 文 | 中文(Chinese) |
| 中文摘要 | 本文主要利用水面有限元素法模式系統,以模擬橋墩設置對河川局部流場所造成的影響。本模式依據Galerkin有限元素法,分析水深平均之二維流場。由於實際河川流場為複雜之三維流況,模式在應用時尚有許多參數,如動量修正參數、動渦度黏滯係數、曼寧n值等需予以估計,因此本文中再依橋墩阻力轉換成河川中摩擦坡度方式,而推求出應用於橋墩附近所應改正之曼寧n值,藉此提供一修正方法以考慮橋墩阻力之影響。為驗證參數修正之適用性,因此本文利用Yarnell (1934)所發表一系列有關橋墩設置對明渠水理影響之試驗資料,針對其中並列橋墩及連續橋墩兩種情況,根據本文所提出之摩擦坡度修正方法進行模擬比較,兩種橋墩情況之結果皆顯示,本文修正後所考慮橋墩阻力時之模擬水位與試驗值較接近,因此修正後之模式較能符合實際流況,最後將此修正後之模式應用於實際之基隆河圓山段,藉以探討中山橋對洪水位所造成的影響,由模擬結果顯示,若將中山橋予以拆除,在200年重現期洪水頻率下,於中山橋上游17斷面間,河川洪水位於中泓線處最大可下降64公分。 |
| 英文摘要 | A depth-averaged two-dimensional Finite Element Surface-Water Modeling System was employed to simulate the local flow field in the river caused by the installation of bridge piers. Because of the three dimensional complicated flow field in the natural river, the parameters, such as the coefficients of momentum correction, kinematic eddy viscosity and Manning roughness are to be determined. Therefore, an adjusted method for correction of the Manning coefficient from increase of friction slope near the bridge piers are developed by the consideration of the drag force due to bridge piers installation. In order to verify the applicability of the adjusted parameters, the experiment data of the parallel and series bridge piers by Yarnell(1934) was simulated and compared. It was shown that the results computed by the present model with friction slope adjustment are better than the ones without adjustment. Finally, the model is applied to the Yuan-shan reach of Keelung river to investigate the influences of flood stage on Chung-shan bridge. According to the simulated results, if the Chung-shan bridge is demolished, the flood stage decreased 64 cm along Thalweg between section 17 and Chung-shan bridge under the flood of 200-yr return period. |
本系統中英文摘要資訊取自各篇刊載內容。