Probabilistic analysis of three different internal erosion mechanisms - Application to a real earth dam

Accident statistics for embankment dams show that internal erosion is a major cause of incidents involving these structures. However, internal erosion is a complex process and remains difficult to assess probabilistically. This technical note presents a probabilistic analysis of internal erosion for an existing embankment dam. The spatial variability of soil properties is modeled using random field theory and incorporated into a finite element seepage analysis. The probabilistic results yield spatial distributions of the means and variances of key hydraulic parameters, such as flow velocity and hydraulic gradient. By applying initiation criteria for three internal erosion mechanisms—backward erosion, suffusion, and contact erosion—the safety of the dam is assessed through the initiation probability ( P f ), derived from the probability distribution of the factor of safety (FoS) for each mechanism. This approach is used to evaluate the probability of internal erosion initiation across different zones of the dam. The results can then be used for risk analysis studies for embankment dams by assessing potential failure scenarios due to internal erosion. • Spatial variability of hydraulic properties modeled via random fields. • Coupled finite element seepage analysis with geostatistical inputs. • Initiation probability estimated for three internal erosion mechanisms. • Real-case application enhances dam safety risk assessment.