不規則波の作用下における小段付き離岸提の平衡断面に及ぼす波形勾配及び初期前面法勾配の影響 Effect of Wave Steepness and the Initial Seaward Slope of Berm Breakwater on Equilibrium Profile of Berm Breakwater under Irregular Wave Attack

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Abstract

不規則波の作用下における,小段付き離岸堤の平衡断面に関する実用的評価式を開発した。前論文では,安定定数,相対小段高さ(小段高さの水深比)と被覆石の粒度分布の3個のパラメータが離岸堤の平衡断面に影響を及ぼすことを述べた。本研究では,さらに波形勾配と離岸堤築堤初期の前面法勾配を考慮した離岸堤の平衡断面の評価式を実験的に見出すことを目的とした。その結果,波形勾配は侵食水平長のみに影響し,侵食鉛直深及び平衡底面幅には影響しないことを見出した。一方,初期前面法勾配は侵食水平長及び平衡底面幅に影響を及ぼすが,侵食鉛直深には影響しないことを見いだした。これらを考慮して,離岸堤の平衡断面に関する新しい評価式を提案した。提案された評価式は,実際の離岸堤の設計に有用な役割を果たすものと考える。

Improved practical fomulas for evaluating the equilibrium profile of berm breakwater under irregular waveattack have been developed.In the previous paper, it has been found that three parameters of the stability number, the relative bermcrest height (ratio of berm crest height and water depth) and the amor grading have significant effects on theequilibrium profile of berm breakwater.For the improvement, the present study was experimentally conducted to find out the conditions of equilibriumprofile of bem breakwater due to effects of the wave steepness and the initial seaward slope of berm breakwater.The results show that, the wave steepness only influences significantly horizontal eroded berm width, howeverit does not significantly influence vertical eroded berm height and toe width. Whereas, the initial seawardslope of berm breakwater influences significantly horizontal eroded berm width and toe width, however it doesnot influence significantly vertical eroded berm height.Considering those results, the new evaluation fomula, which regards the equilibrium section of seaward slopeof berm breakwater, has been proposed. This proposed fomula may be playing an important role in designing aberm breakwater in the actual beach.

Journal

  • Journal of Fisheries Engineering

    Journal of Fisheries Engineering 38(3), 233-238, 2002-02-01

    The Japanese Society of Fisheries Engineering

References:  10

Codes

  • NII Article ID (NAID)
    10008274239
  • NII NACSIS-CAT ID (NCID)
    AN10278554
  • Text Lang
    ENG
  • Article Type
    ART
  • ISSN
    09167617
  • NDL Article ID
    6139475
  • NDL Source Classification
    ZR26(科学技術--農林水産--水産)
  • NDL Call No.
    Z18-1327
  • Data Source
    CJP  NDL  J-STAGE  JASI 
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