Graduation of Casper Broman

Probabilistic assessment of inner slope stability in dikes

• Professor of graduation: Prof. dr. ir. M. Kok

• Supervisors: Dr. ir. C. Mai Van (TU Delft), Dr. ir. M. Korff (TU Delft), Ir. A. Broere (WSP Nederland B.V.), Dr. ir. M. Van der Krogt (Deltares)

After overtopping, the most common failure mechanism in the world that leads to a dike breach is the instability of the inner slope. Two stability calculations are required for the semi-probabilistic assessment of inner slope stability. One calculation is without significant overtopping and the other calculation is with significant overtopping whereby the dike is saturated. The semi-probabilistic assessment method with overtopping is prescribed in a KPR factsheet, but is not verified by calibration calculations or probabilistic calculations. After performing semi-probabilistic and probabilistic calculations at Jaarsveld-Vreeswijk (JAV) in the Netherlands, there seemed to be an inconsistency between the results of inner slope stability with overtopping. Semi-probabilistic and probabilistic calculations have been performed to gain more insight in the inconsistency between the results of inner slope stability with overtopping. Based on the results, it is recommended to perform a calibration study for inner slope stability with overtopping to obtain a better estimate of the failure probability based on semi-probabilistic calculations.