EFFECT OF AVAILABILITY OF LEVEE DATA IN THE ESTIMATION OF THE PROBABILITY OF LEVEE FAILURE IN CASE OF PIPING

摘要

The objective of this study was to demonstrate how different scenarios of data availability along the main river channel, such as geometrical levee characteristics, can affect the estimation of the probability of levee failure and the consequent breach location. To achieve this objective, a four steps methodology is proposed and applied to a case study. Firstly, a reliability function based on the relation between resistance and loading conditions was implemented according to the chosen failure mechanism. Secondly, fragility curves were assessed using the First Order Reliability Method. Then, the estimated fragility curves were classified in different fragility classes, according to the main statistical characteristics of the fragility curves themselves. Finally, different scenarios of data availability, expressed as levee width geometry, were assumed. The proposed methodology was applied to a reach of the Po river, in Italy, between the gauged sections of Cremona (upstream) and Borgoforte (downstream). Based on a statistical analysis of historical levee failure records, piping was considered as main failure mechanism along the study River reach. The results of this study showed how different availability of levee data can affect the estimation of the probability of failure and the consequent identification of spatial location of possible breaches.