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Global sensitivity analysis of dike stability under maximum static groundwater heads
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  • Teun van Woerkom,
  • L.P.H. (Rens) van Beek,
  • Hans Middelkoop,
  • Marc F.P. Bierkens
Teun van Woerkom
Utrecht University

Corresponding Author:t.a.a.vanwoerkom@uu.nl

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L.P.H. (Rens) van Beek
Utrecht University
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Hans Middelkoop
Universiteit Utrecht
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Marc F.P. Bierkens
Department of Physical Geography, Utrecht University
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Abstract

With a large network of dikes that in the future will protect up to 15% of the world’s population from flooding, more extreme river discharges that result from climate change will dramatically increase the flood risk of these protected societies. Precise calculations of dike stability under adverse loading conditions will become increasingly important, though the hydrological impacts on dike stability, particularly the effects of groundwater flow, are often oversimplified in stability calculations. To include these effects, we use a coupled hydro-stability model to indicate relations between the geometry, subsurface materials, groundwater hydrology and stability of a dike regarding soil slip and basal sliding mechanisms. Sensitivity analyses are performed with this model using a large number of parameter combinations, while assessing both the individual sensitivity as combined effects. The analyses show that the material type of the dike and its slope are the more important parameters influencing the stability, followed by the shallow subsurface type and dike crest elevation. The material of the dike and shallow subsurface is additionally important, as a change towards sandier material can either result in either an increase or a decrease of the stability. A database created by an extensive Monte Carlo analysis provides further evidence for these relations and is used to estimate failure probabilities for dike stretches that have not been assessed in detail. Despite the use of a simplified model, not including small-scale heterogeneity, remaining soil strength and transient groundwater flow, the application of the method to a case study proves its applicability.