The void porosity of rock armour in coastal structures

Measurement and payment issues are particularly contentious when dealing with rock armour structures. The paper elaborates upon the fundamental controls of rock fragment packing and progresses to consider rock armour packing and the financial consequences of errors in void porosity assumptions. Results from detailed case studies, construction of full-scale experimental revetments and numerous contracts are summarised in order to compile a data source from which up-to-date guidance on void porosity and layer thickness coefficients can be drawn. A new rapid survey method to assess in-situ packing density and to compare armourstone packing between surface panels is introduced.