Physical Evaluation Of The Hydrodynamic Stability Of An Eco-engineered Armouring Unit

Abstract

ECOncrete®‘s Coastalock is an ecologically designed armour unit, providing an alternative and/or a complement to traditional armour layers with ecologically enhanced armouring that provides shoreline stabilization, while also creating well-defined local ecosystems that mimic natural rock pools. The 2D physical model tests performed at TU Delft focused on the stability, reflection and overtopping of a slope with regularly placed single layer Coastalock armour. The 2V:3H slope had an impermeable core, no wave breaking on the foreshore and no rock toe. The stability was seen to double, with stability number Ns (Ns= Hs/ΔDn50) increasing from roughly 2 to 4 and above, by increasing the porosity between the blocks from spacing the units from 0percent to 25percent. So less concrete use led to more stability. The mean overtopping discharge could be characterized by a roughness factor of gamma_f = 0.610 (for 25percent spacing). A key goal of the Coastalock development is to demonstrate that with the use of innovative eco-engineered armour unit design it is now possible to add ecological considerations into the design process to promote biodiversity and provide ecosystem services, achieving both structural and ecological goals.