Graduation of Daniël Kentrop

05 February 2021 11:00 till 12:30 - Location: Online (MS Teams) - By: Webredactie | Add to my calendar

A Metamodelling Approach to Reliability updating with Dike Construction Survival

  • Professor of graduation: Prof. dr. ir. M. Kok 
  • Supervisors of graduation: Ir. M.G. van der Krogt (TU Delft/Deltares), dr. ir. A.P. van den Eijnden (TU Delft)

The construction of a dike improvement often causes a decrease in reliability during construction. Raising a dike may give rise to excess pore water pressure in the subsoil, resulting in a temporal strength decrease. Observing the survival of such a loading condition might provide information on the strength of a dike. Therefore, this research investigates the effect of incorporating construction survival in estimating the slope reliability of dikes. System reliability is often determined by means of simulation. However, for highly reliable systems like dikes, many realizations are needed to achieve sufficient accuracy, which may lead to infeasible computation times. In this research, a method is developed for reliability updating using metamodelling, providing reasonable computation times while not losing accuracy. This method is applied to a case study dike improvement. The main finding of this research is that incorporating construction survival can be very effective, reducing the probability of failure orders of magnitude. Important parameters for the effectivity of an update are the similarity of probable slope failure modes and the reliability in the both the observed and final situation. Designing the construction sequence of a dike improvement with these parameters in mind can optimize the effect of a reliability update. Additionally, it was shown that adapting the dike improvement design after updating is promising. In the case study, it was found that adapting the dike design after survival of the critical construction step resulted in 75% reduction of the dimensions of the berm to be constructed, while achieving the same reliability as prior to the update.

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