University of Twente Student Theses
Impact of animal burrows on the stability of Dutch dikes : A sensitivity analysis of the effect of relevant animal species on failure mechanisms GEKB and STBI at the IJssel dike
Slootman, L.H. (2024) Impact of animal burrows on the stability of Dutch dikes : A sensitivity analysis of the effect of relevant animal species on failure mechanisms GEKB and STBI at the IJssel dike.
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| Abstract: | This thesis examines the impact of animal burrows on the failure mechanisms GEKB and STBI for the IJssel dike in the Netherlands. The objective of this thesis is to identify the dangers posed by these animal burrows, and to model two of the most impacted failure mechanisms to calculate their impact on the failure rate of dikes. The chosen failure mechanisms are crest settlement due to burrow collapse (GEKB) and sliding of the inner slope (STBI). This is achieved by first conducting an extensive literature review, creating an overview of relevant animal species, their burrow characteristics, which dikes are vulnerable, and which failure mechanisms are impacted. By creating a Microsoft Excel model to simulate burrow collapses in dikes and by using the software Hydra-NL, this study proves that sufficiently large burrows dug by a beaver or badger have the potential to significantly increase the probability of failure due to the GEKB mechanism. Beavers may increase the failure rate due to GEKB by a factor ranging between 1 - 1.8, while the badger may impact this by a factor of 1 - 2.4. Muskrats and nutria were determined to not impact this mechanism significantly. These numbers are based solely on the IJssel dike, and are not applicable to every dike in the Netherlands. By using PLAXIS 2D, it was determined that animal burrows have a negative impact on the STBI mechanism as well. This is the case for a dike with a sand core, the tested dikes with clay cores were not impacted significantly. Burrows were determined to only have small impact on clay core dikes for the failure mechanism STBI, only increasing the failure rate by a factor of 1 - 1.2. For sand cores, animal burrows can impact the failure rate by a factor of 1 - 6.0. An impact of this size can only be attributed to the beaver. Other species can impact sand cores by a factor of 1 - 2.0. In the end, it was concluded that burrows do impact GEKB and STBI for the IJssel dike. The size of the impact is not large enough to cause immediate concerns, but it is large enough to potentially make dikes fail to meet safety requirements. Because of this, it can be recommended to take measures against them. It should be noted that these conclusions are drawn based on the large IJssel dike, and that the impact on failure rate might be different for smaller dikes. |
| Item Type: | Essay (Bachelor) |
| Faculty: | ET: Engineering Technology |
| Programme: | Civil Engineering BSc (56952) |
| Link to this item: | https://purl.utwente.nl/essays/103832 |
| Export this item as: | BibTeX EndNote HTML Citation Reference Manager |
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