AbstractThe XblocPlus is a new type of interlocking single layer armour units that is placed with uniform orientation. This is novel and different from all other single layer, interlocking armouring systems. The hydraulic stability of the XblocPlus breakwater armour unit was tested in 2D and 3D hydraulic model tests. Wave overtopping tests were performed to determine the roughness coefficients of the EurOtop overtopping formula for the XblocPlus. Model tests on a rubble mound breakwater with XblocPlus armour included 2D tests with a 1:30 seabed slope and with 1:2 and 3:4 breakwater slopes and 3D model tests with a flat seabed and with a 3:4 breakwater slope. Wave heights up to 150% of the design wave height were tested in the 2D tests and up to 200% with wave directions 0° to 60° in the 3D tests. No armour unit displacements were observed in 2D tests with 1:2 slope. In the 2D tests with 3:4 slope one armour unit was displaced when the wave height reached 159% of the design wave height. No damage to the XblocPlus armour layer was observed in the 3D tests. A roughness coefficient of 0.45 was deduced from overtopping tests with wave heights of 60% to 100% of the design wave height. The model test results indicate little or no influence of wave steepness on XblocPlus stability and no adverse influence of wave obliquity while the seabed slope in front of the breakwater may have some impact on the XblocPlus armour layer stability.
Bakker, P., B. Reedijk, J. Manaois, M. van de Koppel, M. Muttray, Causes for increased wave overtopping on rubble mound breakwaters and revetments. ICE, Proc. Coasts, Marine Structures and Breakwaters 2017, Liverpool, UK (2017).
Berg, I. van den, Effect of irregularities in the under layer on the stability of XblocPlus concrete armour unit. MSc Thesis, Delft University of Technology, Delft, Netherlands (2018).
DMC, Guidelines for Xbloc concept design. Delta Marine Consultants, Gouda, The Netherlands, https://www.xbloc.com (2018).
EurOtop, Manual on wave overtopping of sea defences and related structures. 2nd Edition, www.overtopping-manual.com (2018).
Jacobs, R., P. Bakker, I. Vos-Rovers, B. Reedijk, XblocPlus - Development of a regular placed interlocking armour unit. Poster, ASCE, 36th International Conference on Coastal Engineering, Baltimore, Maryland (2018).
Janssen, D., Stability analysis of XblocPlus crest element. MSc Thesis, Delft University of Technology, Delft, Netherlands (2018).
Mansard, E.P.D., E.R. Funke, The measurement of incident and reflected spectra using a least squares method. ASCE, Proc. 15th International Conference on Coastal Engineering, Sydney, Australian (1980).
Muttray, M., B. Reedijk, Design of concrete armour layers. Hansa, International Maritime Journal, Vol. 146, No. 6, pp. 111-118 (2009).
Muttray, M., J.S. Reedijk, I. Vos-Rovers, P. Bakker, Placement and structural strength of Xbloc and other single layer armour units. Proc. Coastlines, Structures and Breakwaters, ICE, pp. 556-567 (2005).
Pearson, Y., J.van der Meer, T. Bruce, L. Franco, Overtopping performance of different armour units for rubble mound breakwaters. International Coastal Symposium, Höfn, Iceland (2005).
Rada Mora, M.B., Hydraulic performance of XblocPlus armour unit. MSc Thesis, Delft University of Technology, Delft, Netherlands (2017).
Reedijk, B., M. Muttray, H. Bergmann, Risk Awareness - Key to a sustainable design approach for breakwater armouring. Proc. Coasts, Marine Structures and Breakwaters: Adapting to change, Vol. 1, pp. 96-107, (2010).
Vos, A. Exploration into the mechanisms that govern the stability of an XblocPlus armour unit. MSc Thesis, Delft University of Technology, Delft, Netherlands (2017).