The main advantages of the XblocPlus are:
- Increased safety margin in adopted stability number
- Lowest concrete consumption compared to other available armour units (same as Xbloc)
- 25%-35% less units to cast and place
- Fast and easy block placement
- Aesthetic appearance of the XblocPlus armour layer
XblocPlus - General
The XblocPlus has been developed based on the experience that DMC has gained with numerous Xbloc projects around the world. XblocPlus units are designed for regular placement. This allows crane operators to place units fast and efficiently without searching for the optimal block orientation relative to the blocks already placed. The placement of XblocPlus is a bit like rooftiles. This results in a smooth appearance of the slope which can be preferable for architectural reasons. The XblocPlus units are ideal for placement on straight and mildly curved breakwater sections and shore protection. For sharp curves and breakwater roundheads XblocPlus units can be combined with Xbloc units which allow for more flexible placement.
Artist impression of XblocPlus on the breakwater trunk in combination with Xbloc on the breakwater head
XblocPlus units have been designed to achieve optimal interlocking between the blocks. The two ‘wings’ of the block are securely locked behind the vertical edges of the two blocks in the row underneath. This prevents the units from sliding out of their position and therefore, increases the hydraulic stability of the armor units. The hole in the centre of the unit reduces the water overpressures during wave run-up and run-down, reducing the wave forces on the units. The hole can also be used to lift and place the blocks with a hydraulic clamp. This makes placement easy and safe since one crane operator can perform the placement process on his own without help of other personnel on site.
XblocPlus units have been tested extensively during numerous 2D and 3D model tests. During these tests the adopted stability number which relates to the hydraulic stability of the units was confirmed. Even tests with 250% of the design wave height did not lead to damage of the XblocPlus armor layer. The adopted design stability number of the XblocPlus thus includes a large safety margin.
By choosing a relatively low design stability number the XblocPlus units are becoming bigger and therefore cover a larger area on the slope. This leads to a reduction in the number of units needed to cover the slope and consequently a reduced number of blocks to cast, store and place. Even though the block size is increased for XblocPlus as compared to Xbloc, the concrete consumption per area on the breakwater or shore protection is still the same for XblocPlus and Xbloc.