Reliability updating and decision analysis for head monitoring of levees
article
Flood defence levees are crucial for flood protection, especially in riverine and deltaic areas. One of the most critical failure modes of levees is backwards internal erosion or piping. Piping reliability is largely influenced by uncertainties in ground conditions, especially by geohydrological properties such as the hydraulic conductivity of an aquifer. These properties are typically highly uncertain, which can lead to the related probabilities of failure being considerably high. Ways to reduce such uncertainties are by performing additional site investigation, incorporating information from field performance observations or monitoring. After providing some background on uplift and piping, the paper shows how Bayesian posterior analysis can be done using head monitoring observations in aquifers during extreme floods. The approach will be demonstrated by means of an illustrative example using a simplified uplift model showing also how the posterior distributions of the basic random variables change with respect to their priors. Subsequently, it will be illustrated how uncertain future measurements can be used in pre-posterior analysis to support decisions on investments in monitoring. The results suggest that the uncertainties in geohydrological conditions can be reduced significantly and that, if the monitoring cost is low compared to potential retrofitting measures, monitoring can be cost-effective. © 2013 Copyright Taylor and Francis Group, LLC.
Topics
TNO Identifier
474199
ISSN
17499518
Source
Georisk, 7(2), pp. 110-121.
Pages
110-121
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