Flood embankments are a key asset in flood defence systems; assessing their
probability of failure is therefore important for the evaluation of flood hazard. Flood
embankments, however, can reach lengths of thousands of kilometres. Probability of
failure assessments are complex and expensive, which limits their applicability on
such a large scale. This challenge highlights the need to develop both a simple
probabilistic approach that does not require excessive time or computational effort,
and an affordable method for the deterministic hydro-mechanical characterisation of
flood embankments that can easily be extended to long segments.
This thesis addresses these challenges by first focusing on the development of an
accessible probabilistic method that accounts for uncertainties in the soil properties
and hydrological loading. This approach benefits from the simple First Order Second
Moment method while addressing its main limitation, namely the assumed
probability distribution of the Factor of Safety. The approach is successfully
validated against its ability to capture the annual probability of failure of a segment
of the Adige River embankment that experienced instability of the landside slope.
The hydro-mechanical model of the embankment is characterised via site
investigation and laboratory tests. In particular, the hydraulic model is characterised
via inverse analysis of water flow in the saturated and unsaturated zones based on
field monitoring data. However, this approach may be difficult to extend to long
segments of the embankment, given the challenge to monitor water flow on a large
scale. In order to address this issue, the use of Electrical Resistivity Tomography
(ERT) for monitoring of water flow is investigated. Results show that ERT can be a
valuable tool to quantify water content if a field-specific relationship between water
content and ERT-measured resistivity is calibrated.
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The case study of the Adige River embankment is further analysed to investigate the
factors governing the water flow and stability of the embankment. Comparison of the
water flow regime between two sections, located within and outside the failure
segment, highlights the critical role played by the hydraulic response of the material
on the landside outside the footprint of the embankment. This key finding can
support the decision-making process when planning site investigation aimed to the
stability assessment of flood embankments.
These outcomes combine to provide a flexible approach for the probabilistic stability
analysis of flood embankments that can be easily adapted and applied to different
contexts with limited levels of investment of time and resource. This approach may
be developed into a suitable tool for the routine hazard assessment of the stability of
flood embankments.
| Date of Award | 29 May 2018 |
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| Original language | English |
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| Awarding Institution | - University Of Strathclyde
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| Sponsors | University of Strathclyde |
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