Experimental study on mechanism of sea-dike failure due to wave overtopping

Zhang, Yao; Chen, Gang; Hu, Jinchun; Chen, Xinping; Yang, Weixuan; Tao, Aifeng; Zheng, Jinhai

doi:10.1016/j.apor.2017.08.009

Cited by 17 publications

(19 citation statements)

References 54 publications

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“…When this wave overtopping occurs, it possibly causes structural failure and further leads to potential seawall breaching. In this study, we determine the location and width of seawall breaches along the coast of Shanghai using the recommended values for wave overtopping threshold (~20 l/m/s), which are derived from a large number of wave flume experiments (Zhang et al, 2017) and proposed by the National Guidelines of Marine Disaster Risk Assessment for the evaluation and anticipation of dike failures in China.…”

Section: 1029/2020ef001614mentioning

confidence: 99%

Flood Risks in Sinking Delta Cities: Time for a Reevaluation?

et al. 2020

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Sea level rise (SLR) and subsidence are expected to increase the risk of flooding and reliance on flood defenses for cities built on deltas. Here, we combine reliability analysis with hydrodynamic modeling to quantify the effect of projected relative SLR on dike failures and flood hazards for Shanghai, one of the most exposed delta cities. We find that flood inundation is likely to occur in low‐lying and poorly protected periurban/rural areas of the city even under the present‐day sea level. However, without adaptation measures, the risk increases by a factor of 3–160 across the densely populated floodplain under projected SLR to 2100. Impacts of frequent flood events are predicted to be more affected by SLR than those with longer return periods. Our results imply that including reliability‐based dike failures in flood simulations enables more credible flood risk assessment for global delta cities where conventional methods have assumed either overtopping only or complete failure.

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Section: 1029/2020ef001614mentioning

confidence: 99%

Flood Risks in Sinking Delta Cities: Time for a Reevaluation?

et al. 2020

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“…Multiple studies have indicated that horizontally and vertically varying hydraulic variables such as the pressure, normal stress, shear stress and shear velocities are important to understand failure by cover erosion or instability [9,[13][14][15]. The pressure and normal stresses are required to compute the forces due to wave impact [15].…”

Section: Introductionmentioning

confidence: 99%

“…The pressure and normal stresses are required to compute the forces due to wave impact [15]. Zhang et al [14] identified cover erosion caused by a combination of normal and shear stress as the main mechanism of dike failure. The pressure on vertical walls by overtopping waves has been measured in experiments [13,14].…”

Section: Introductionmentioning

confidence: 99%

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Modelling the Wave Overtopping Flow over the Crest and the Landward Slope of Grass-Covered Flood Defences

Bergeijk

Warmink

Hulscher

2020

JMSE

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The wave overtopping flow can exert high hydraulic loads on the grass cover of dikes leading to failure of the cover layer on the crest and the landward slope. Hydraulic variables such as the near bed velocity, pressure, shear stress and normal stress are important to describe the forces that may lead to cover erosion. This paper presents a numerical model in the open source software OpenFOAM® to simulate the overtopping flow on the grass-covered crest and slope of individual overtopping waves for a range of landward slope angles. The model provides insights on how the hydraulic forces change along the profile and how irregularities in the profile affect these forces. The effect of irregularities in the grass cover on the overtopping flow are captured in the Nikuradse roughness height calibrated in this study. The model was validated with two datasets of overtopping tests on existing grass-covered dikes in the Netherlands. The model results show good agreement with measurements of the flow velocity in the top layer of the wave, as well as the near bed velocity. The model application shows that the pressure, shear stress and normal stress are maximal at the wave front. High pressures occur at geometrical transitions such as the start and end of the dike crest and at the inner toe. The shear stress is maximal on the lower slope, and the normal stress is maximal halfway of the slope, making these locations vulnerable to cover failure due to high loads. The exact location of the maximum forces depends on the overtopping volume. Furthermore, the model shows that the maximum pressure and maximum normal stress are largely affected by the steepness of the landward slope, but the slope steepness only has a small effect on the maximum flow velocity and maximum shear stress compared to the overtopping volume. This new numerical model is a useful tool to determine the hydraulic forces along the profile to find vulnerable points for cover failure and improve the design of grass-covered flood defences.

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“…Su propósito es redirigir y alejar las líneas de corriente que inciden en la margen, evitando así problemas de erosión y arrastre de material. Existen estudios que reportan el funcionamiento hidráulico de los espigones, desde simulaciones numéricas (Mawandha, Wignyosukarto, & Jayadi, 2018;McCoy, Constantinescu, & Weber, 2007a;McCoy, Constantinescu, & Weber, 2008) hasta estudios de laboratorio (Kang, Yeo, Kim, & Ji, 2011;Weitbrecht, Socolofsky, & Jirka, 2008;Zhang et al, 2017). En su 2020, Instituto Mexicano de Tecnología del Agua Open Access bajo la licencia CC BY-NC-SA 4.0 (https://creativecommons.org/licenses/by-nc-sa/4.0/) mayoría, estos trabajos se limitan a estudiar espigones que emergen de la superficie libre del agua y están colocados de forma perpendicular a la margen; siendo los espigones sumergidos y los orientados a un cierto ángulo con la orilla los menos estudiados (McCoy, McCoy, Constantinescu, & Weber, 2007b;Jiménez-León, Mendiola-Lizárraga, Rivera-Trejo, Nungaray-Núñez, & Díaz-Arcos, 2017).…”

Section: Introductionunclassified

Protección marginal con espigones, simulación numérica 1D

Rivera-Trejo

Hernández-Cruz

2020

Tecnol. cienc. agua

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Experimental study on mechanism of sea-dike failure due to wave overtopping

Cited by 17 publications

References 54 publications

Flood Risks in Sinking Delta Cities: Time for a Reevaluation?

Flood Risks in Sinking Delta Cities: Time for a Reevaluation?

Modelling the Wave Overtopping Flow over the Crest and the Landward Slope of Grass-Covered Flood Defences

Protección marginal con espigones, simulación numérica 1D

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