碩士 / 國立成功大學 / 水利及海洋工程學系碩博士班 / 90 / The characteristics of scouring and depositing in the vicinity to a seawall is preliminarily studied in the thesis, by the irregular wave experiments in a sand bed flume.
Referring to the section profile of southwestern coast and seawalls, the layout in the flume is made with a model scale of 1/15; the sand bed in slope of 1:30 nearshore and 1:80 offshore, a seawall with a slope of 1:1.5 and crest width of 26.7cm, as well as two kinds water depths (13.3 cm , 21.3 cm) at the toe of seawall. While a sequent of irregular waves were generated with T1/3 =2.07, 2.58, 3.1 and 3.61sec, breaking wave height, wave height in front of the seawall, run-up along the seawall slope and scouring depth of sand beach were measured simultaneously for dimensionless analysis.
The results reveal that the maximum scour depth Δds,max shows a good relation with the wave height in front of the seawall and most 2% larger run-up, and scouring parameterΔds,max/dt presents a natural-logarithmic correlation with Shields' number Ψm , in which dt=water depth at the toe of seawall. With regression of experimental data, the empirical formula of the maximum scour depth and width, the maximum deposit height and position were also suggested in this study.
The concept of the equivalent scouring durations te was proposed to obtain the relationship of the dimensionless scouring depth Δd/Δds,max and time scale te/ts,max in this study (Δd=temporal scouring depth at te ; ts,max=total duration when Δds,max happens).Thus the temporal development of the scouring depth at the toe of seawall could be evaluated and used to assess the seawall safety during a sequent wave attacking.
| Identifer | oai:union.ndltd.org:TW/090NCKU5083034 |
| Date | January 2002 |
| Creators | Chune-Wei Huang, 黃俊維 |
| Contributors | Chung-Ho Chien, 簡仲和 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 66 |
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