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Please use this identifier to cite or link to this item: http://ntour.ntou.edu.tw:8080/ir/handle/987654321/34321

Title: 波浪通過多列帷幕牆式防波堤交互作用之研究
Wave Interactions with Multiple-Row Curtainwall-Pile Breakwaters
Authors: 岳景雲
Contributors: NTOU:Department of Harbor and River Engineering
Keywords: 反射;透過;群樁式防波堤;帷幕牆式防波堤
reflection;transmission;pile-type breakwater;curtainwall-pile breakwaters
Date: 2012-08
Issue Date: 2013-10-07T02:25:46Z
Publisher: 行政院國家科學委員會
Abstract: 摘要:港灣工程中防波堤種類可分為拋石堤、直立堤、合成堤及其他特殊型式防波堤。防 波堤興建完工後可以使得堤後方遮蔽區得到一靜穩水域,讓船舶安全停泊與卸貨,但是 也阻擋了沿岸漂沙輸送,採用合成堤型式,又必須使用較多消波塊、護基方塊來保護堤 身,使得施工成本及時間相對增加很多,因此有必要發展新型式防波堤。 群樁式防波堤屬於非重力式防波堤之一種,是由很多根樁相互平行而組成,其消波 機制主要是利用波浪通過樁距產生亂流及利用群樁表面摩擦來消滅波能,大部分適用於 軟弱地質及外海波浪相對較小處,其與傳統防波堤最主要不同點是下部結構透水允許漂 沙通過,不致於造成下游區侵蝕。 帷幕牆式防波堤(CPB)是由上半部為不透水結構,而下半部是由群樁支撐組合而 成,為了保護較小港區,採用帷幕牆式防波堤或許是一有利之選擇,因為與重力式防波 堤比較,其工程建造費用較節省,對環境衝擊影響較小。但是由於單列式CPB 對長週 期波浪通過時其透過率仍大,消波效果不是很好,過去為了降低其透過率,一般可以採 用增加上半部不透水結構物沒水深度,或是減少樁距使得孔隙率降低,即可降低透過 率,但反而會使反射率變大,作用於CPB 結構物波力也會增加,此時採用多列式CPB 或許可以解決上述之問題,即反射率、透過率、及波力都相對降低。 本計畫的目的在利用多領域邊界元素法(Multi-domain BEM),建立一套數值模式, 探討波浪通過多列帷幕牆式防波堤(CPB)其消波特性。並可與翼板式及群樁式防波堤作 一整合及比較。
abstract:Breakwaters can broadly be classified as rubble-mound breakwaters, vertical breakwaters, composite breakwaters, and special types of breakwater. Breakwaters create a tranquility condition on their leeward side that is essential for safe maneuvering and berthing of vessels, and they intercept the movement of a long-shore sediment transport and prevent sediments from depositing in the approach channel. Construction of composite breakwaters in deep sea areas requires more wave-dissipating blocks and, thus significant construction cost and time. For these reasons, new types of breakwaters have been developed. The pile-type breakwater is a typical nongravity type consisting of rows of piles parallel to each other to partially attenuate the wave. The wave attenuation by pile breakwaters is mainly due to the turbulence developed around the piles, which is the results of skin drag around the piles. The pile breakwaters are normally built in relatively calm seas with soft soil foundation. The important advantage of pile breakwaters is that they allow free passage of sediment, thereby reducing the potential errosion on the down-drift side that is normally a result of the construction of a conventional rubble mound breakwater. A curtainwall-pile breakwater(CPB), the upper part of which is a curtain wall and the lower part consists of an array of vertical piles, may be a useful alternative to gravity-type breakwaters, for protecting small craft harbors. In general, a CPB allows smaller construction cost and less environmental impacts compared with conventional gravity-type breakwater. Since single row CPB still gives large transmission for long-period waves. To reduce the wave transmission, the draft of the curtain wall must be increase or the porosity between the piles must be decreased. Then, however, the wave reflection and the wave force and moment acting on the breakwater may increase. Therefore, a multiple-row CPB may be a solution for these problems. The purpose of the present project is to present a numerical model(Multi-domain BEM)developed to predict the hydrodynamic performance characteristics of multiple-row curtainwall-pile breakwaters.
Relation: NSC101-2221-E019-020
URI: http://ntour.ntou.edu.tw/handle/987654321/34321
Appears in Collections:[河海工程學系] 研究計畫

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