Coastal dyke structure for tsunami energy reduction by scour formation

• Project/Area Number: 16K18153
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Hydraulic engineering
• Research Institution: Tohoku Gakuin University (2017-2018); Tohoku University (2016)
• Principal Investigator: MITOBE Yuta 東北学院大学, 工学部, 講師 (60700135)
• Research Collaborator: KANEKO Yuto ; ABE Koyuki
• Project Period (FY): 2016-04-01 – 2019-03-31
• Project Status: Completed (Fiscal Year 2018)
• Budget Amount: ¥3,640,000 (Direct Cost: ¥2,800,000、Indirect Cost: ¥840,000); Fiscal Year 2018: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000); Fiscal Year 2017: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2016: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
• Keywords: 海岸堤防 / 津波 / 局所洗掘 / 減災効果 / 水理実験 / 数値実験 / 数値計算 / 移動床実験 / 越流 / 洗掘 / 防災

Outline of Final Research Achievements

Tsunami overflow causes local scour behind coastal dykes. The scour has been known as one of the main cause of the destruction of dykes by the 2011 tsunami, while it is pointed out that the scour absorbed the tsunami energy to reduce the damages behind them. In this research, the process of the scour development and its effect of tsunami energy reduction were investigated through hydraulic experiments, and the empirical model was proposed to calculate them in numerical simulations of tsunami inundation. Based on the proposed model, numerical experiments were conducted to discuss proper toe structures of coastal dykes to reduce the tsunami energy for disaster reduction measures.

Academic Significance and Societal Importance of the Research Achievements

この研究で得られた成果は今後も発生する巨大津波に対する対策として重要な役割を担う海岸堤防について、その構造の決定に有用な知見を与えるものである。さらに研究の中で得られた洗掘の発達過程およびエネルギー減衰効果の経験式によるモデルを組み込むことで、一般的な津波氾濫計算においてそれらの減災効果を評価することが可能となる。個々の地域特性や想定津波に対し、最適な海岸堤防を検討するための有用なツールとなるものである。

Research Products

• [Journal Article] LOCAL SCOUR BEHIND COASTAL EMBANKMENTS DUE TO TSUNAMI OVERFLOW AND ITS EFFECT ON TSUNAMI ENERGY REDUCTION (2017)
  • Author(s): 金子祐人，三戸部佑太，田中 仁，会田俊介，小森大輔
  • Journal Title: Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering) Volume: 73 Issue: 2 Pages: I_871-I_876
  • DOI: 10.2208/kaigan.73.I_871
  • NAID: 130006171883
  • ISSN: 1883-8944, 1884-2399
  • Peer Reviewed / Open Access
• [Journal Article] EXPERIMENT ON VELOCITY FIELD IN SCOURING AND REDUCTION EFFECT BEHIND COASTAL DIKES BY TSUNAMI OVERFLOW (2016)
  • Author(s): 金子祐人, 三戸部佑太, 乙志和孝, 黒澤辰昭, 田中 仁, 小森大輔
  • Journal Title: Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering) Volume: 72 Issue: 2 Pages: I_913-I_918
  • DOI: 10.2208/kaigan.72.I_913
  • NAID: 130005282429
  • ISSN: 1883-8944, 1884-2399
  • Peer Reviewed / Acknowledgement Compliant
• [Presentation] 海岸堤防裏法尻の洗掘孔の発達過程と津波減勢効果に関する水理実験 (2017)
  • Author(s): 三戸部 佑太
  • Organizer: 第64回海岸工学講演会
• [Presentation] 海岸堤防裏法尻の洗掘孔内の流れ場と流速低減効果に関する水理実験 (2016)
  • Author(s): 金子祐人, 三戸部佑太, 乙志和孝, 黒澤辰昭, 田中 仁, 小森大輔
  • Organizer: 第63回海岸工学講演会
  • Place of Presentation: 大阪大学中之島センター（大阪府大阪市）
  • Year and Date: 2016-11-16