Geogrid-based countermeasures against scour behind coastal dikes under tsunami overflow. Issue 1 (2nd January 2020)

• Record Type: Journal Article
• Authors: Takegawa, Naoki; Sawada, Yutaka; Kawabata, Toshinori
• Is Part Of: Marine georesources & geotechnology. Volume 38:Issue 1(2020)
• Page Start: 64
• Page End: 72
• Publication Date: 2020-01-02
• Subjects: Coastal dike -- tsunami overflow -- scour -- countermeasure -- geogrid -- liquefaction -- model experiment; Marine mineral resources -- Periodicals; 551.46
• DOI: 10.1080/1064119X.2018.1552998
• Languages: English
• ISSNs: 1064-119X

Abstract

Abstract: Following the Great East Japan Earthquake, a massive tsunami caused serious damage to coastal dikes. Local scour at the ground behind these dikes reportedly causes dike failures. It is important to reveal the scour process to establish methods for effective scour countermeasures. Herein, we focus on geogrids. To verify this proposal and examine its design, flume-model experiments were performed for non-liquefied and liquefied grounds behind coastal dikes. The results showed that the scour amount and area were reduced drastically when geogrids were present. Geogrids on the sand-bed surface changed the direction of overflow water. Thus, a scour hole developed away from a coastal dike model. Furthermore, geogrids exerted a scour-reduction effect even during liquefaction.