How to Cite

STABILITY OF XBLOCPLUS ARMOUR LAYERS AFTER INITIAL DAMAGE. (2020). Coastal Engineering Proceedings, 36v, structures.16.


XblocPlus is an interlocking single layer armour unit that is placed with uniform orientation. The unit is applied with a large safety margin. Physical model test were performed without damage up to stability numbers of Hs/dDn=5.5 whereas a design stability number of Hs/dDn=2.5 has been adopted. The behaviour of an XblocPlus armour layer after initial damage is has been investigated by physical model tests with broken and manually removed model units. XblocPlus armour layers (with uniform orientation) respond differently to initial damage than interlocking armour units with random orientation. The latter are moving and re-arranging in order to bridge a gap in the armour layer (de Rover et al., 2008). XblocPlus units in contrast hardly move and nonetheless maintain the hydraulic stability of the damaged section. Details of the experiments and findings as well as implications for design and maintenance of breakwater armour layers will be discussed in the final paper.

Recorded Presentation from the vICCE (YouTube Link):


De Hoop (2019): Gevolgen van beschadigde XblocPlus golf-brekerblokken voor stabiliteit. Thesis, De Haagse Hogeschool (in Dutch)

De Rover, Verhagen, van den Berge, Reedijk (2008): Breakwater stability with damaged single layer armour units. Proc. 31st Int. Conf. Coastal Engineering, Hamburg, Germany.

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