Graduation of Amber Vos

16 August 2017 15:00 - Location: Room E, Faculty of Civil Engineering and Geosciences

“Exploration into the mechanisms that govern the stability of a Xbloc+ v1 armour unit” | Professor of graduation: Prof. dr. ir. S.G.J. Aarninkhof (TU Delft), supervisors: Ir. H.J. Verhagen (TU Delft), Dr.ir. B. Hofland (TU Delft), Ir. B. Reedijk (BAM Infraconsult bv), Ir. R. Jacobs (BAM Infraconsult bv).

In this MSc thesis it is investigated how the first version of concrete armour unit Xbloc+, Xbloc+ v1, acquires its stability. The stability mechanisms are investigated by conducting two type of physical model tests. First, 23 dry pull-out tests are done to obtain insights into the aspects and mechanisms that influence the armour layer stability. At 8 locations per slope, blocks are pulled out to determine the force needed 2 extract an armour unit. Tests are done on a 3:4 slope with 2 pull-directions; under an angle of 45 degrees with respect to the slope and perpendicular to the slope. Concrete as well as plastic armour units are tested, both having a different surface roughness. The conclusions of the pull-out tests are verified by means of the second type of model tests; small scale physical hydraulic model tests in a 2D wave flume. In total, 10 tests are conducted; 6 tests with plastic armour units and 4 tests with concrete armour units. Each test starts with a run with a small significant wave height which is increased stepwise in each run until failure occurs. All test sections have a 3:4 slope and are subjected to waves with a 4% steepness. Additionally, the influence of the significant wave height step size for successive runs is investigated. The combination of both physical model tests results in recommendations for a change in design which is expected to lead to a higher stability of an armour layer with Xbloc+ armour units.

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