Numerical modelling of armour layers with reference to Core-Loc units and their placement acceptance criteria

For the numerical creation of full-scale Core-Loc armour layers, a placement method was briefly introduced in previous work by the authors, based on the multi-body FEMDEM code, Y3D-R combined with a versatile deposition code, POSITIT. While satisfactory layers were previously demonstrated, here we elaborate on the sensitivity of the placed armour layer attributes to the numerical construction process parameters. In this work, new capabilities of POSITIT/Y3D-R are harnessed in a computationally efficient row-by-row numerical placement of units. These include vibration and artificially low friction in order to achieve acceptable irregular packs of the appropriate packing density. To examine the role that initial armour layer build quality has on unit immovability or the percentage of units that do not displace significantly under a standard oscillatory disturbing force, a sinusoidal velocity vibration is applied to the foundations in a series of tests on differently constructed full-scale armour layers. What emerges from this sensitivity study is an implicit verification of the importance of the technical requirements set by the developer of Core-Loc units.