Generation and simple sensitivity analysis of fragility surfaces generated for two failure mechanisms in river levees for flood risk analysis using monte carlo simulations

Levee failure mechanisms have been studied and mathematically described by several authors. However, as some variables may follow stochastically distributed values, the statistical analysis may prove to be difficult and resource consuming. In this paper, Monte Carlo simulations were used to generate fragility curves for two failure mechanisms (overtopping and piping) which represent the behavior of a given levee when facing certain hydrological conditions. This surfaces might be used afterwards in a more complete flood risk analysis. Furthermore, a simple sensitivity analysis was carried out to determine the impact that some geometric variables had on the failure probability surfaces. The results of this analysis suggest that the levee's failure probability due to overtopping is more sensitive to the levee's taluses than to the levee's crest height and width, while the failure probability due to piping is more dependent on the sand layer's thickness than on the seepage length.