Strength resistance of sea dikes to increased wave overtopping due to the rise in sea levels
Strength resistance of sea dikes to increased wave overtopping due to the rise in sea levels
The predicted rise in sea levels due to climate change results in the requirement to increase the height of coastal dikes in order to maintain current safety levels. The extraction of suitable natural clay material for dike coverings is significantly restricted. Therefore, this study will consider dredged material as an alternative and if higher wave overtopping rates can be tolerated. Field tests with simulated water infiltration rates similar to those of a storm surge event at existing dikes were conducted. Soil samples were subsequently taken and examined in the laboratory, e.g. by triaxial tests. The results showed, that dredged material with a certain clay content is as suitable for dike coverings as glacial till and soft marsh soil, which are commonly used for dike coverings in estuaries resp. the Baltic Sea region. Measurements by vane tests directly after a storm surge event revealed different soil strengths across the dike, whereby the future highest hydraulicly loaded areas showed the lowest but still sufficient strength resistances. In an explicit numerical simulation model all field and laboratory test results were merged. For simulating the non-static wave overtopping at the dike crest, shear forces were applied at distinct dike surface areas. By defining a failure criterion for a progressing erosion process and high overtopping rates, a dike failure similar to observed ones in the past could be simulated.
Martin Pohl; Thomas Nuber; J. Moreno
18th European Conference on Soil Mechanics and Geotechnical Engineering (ECSMGE2024)
C - Risk analysis and safety evaluation
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