SLIDING STABILITY OF LANDWARD SLOPE CLAY COVER LAYERS OF SEA DIKES SUBJECT TO WAVE OVERTOPPING

Andre van Hoven, Bianca Hardeman, Jentsje W. van der Meer, Gosse Jan Steendam

Abstract


Sea dikes with landward slopes covered by grass and clay cover layers, subject to wave overtopping, can become unstable and slide. Sliding stability of the cover layer is caused by a decrease in shear strength due to an increase in pore pressure in and underneath the clay cover layer. This holds for both clay dikes and sand dikes with a clay cover layer. A method is presented to determine the potential pore pressure build up due to a storm event with wave overtopping. The method combines of the shelf knowledge and is supported by laboratory measurements and field measurements during prototype scale wave overtopping tests and sliding test on Dutch sea dikes. The method contains three steps: 1) determine the infiltration time, depending on the storm duration and the sea state; 2) determine the infiltration capacity of the dike slope, either by choosing a safe value or field measurement and 3) determine the potential pore pressure build up, determined by step 1) and 2) and the dike structure and geometry. The potential pore pressure build up can be used in the standard stability analyses tools published in Dutch guidelines on dike design and dike safety assessment.

Keywords


sliding stability; sea dike; clay cover; infiltration; wave overtopping

References


Rijkswaterstaat 1961. Verslag over de stormvloed van 1953.Rijkswaterstaat, Koninklijk Nederlands Meteorologisch Instituut, Staatdrukkerij en uitgeverijbedrijf 's-Gravenhage 1961 (in Dutch); Report on the stormsurge of 1953.

TAW 2001. Technisch Rapport Waterkerende Grondconstructies, Geotechnische aspecten van dijken, dammen en boezemkaden, Technische Advies Commissie voor de Waterkeringen (in Dutch);Technical Report on soil based water defences, geotechnical aspects of dikes, levees and regional defences. Technical Advisory Committee for Water Defences.

TAW 2002, Technical report on wave run-up and wave overtopping, Technical Advisory Committee for Water Defences, May 2002

TAW 1996, Technisch Rapport Klei voor Dijken (In Dutch), Technical report on the use of clay for dikes, Technical Advisory Committee for Water Defences, May 1996

Van Hoven, A. 2008, Sterkte van Kleibekleding bij Golfoverslag, invloed van gras en bodemstructuur op de sterkte van klei (in Dutch), Strength of clay cover layers, the influence of grass and soil structure on the shear strength of clay, Delft Cluster, rapnr. 418020.0011, april 2008

Van Hoven, A., Barends, F.B.J., 2010, A practical approach for infiltration tests, Proceedings FSST 2010

Van der Meer J.W., G.J. Steendam, G. de Raat, P. Bernadini, 2008. Further developments on the wave overtopping simulator, ASCE, proc. ICCE, Hamburg

Van der Meer, J.W., W. Snijders and E. Regeling, 2006. The wave overtopping simulator. ASCE, proc. ICCE, San Diego.


Full Text: PDF

Creative Commons License
This work is licensed under a Creative Commons Attribution 3.0 License.