The majority of rubble mound coastal structures contain granulair filters, often with one or more layers. These filters are normally geometrically tight filters. These filters can be difficult to realize in some circumstances. An alternative is a geometrically open filter. Applying an open filter may lead to a reduction in the number of layers. However, the layer thikness may have to be increased compared to a layer thickness in a geometrically tight filter.
In order to improve the knowledge on the behaviour of open granular filters under wave loading, laboratory experiments have been conducted in a flume. The physical model tests focussed on a sloped granular filter construction (slope 1 :7), placed directly on sand with a wide filter gradation. The physical model tests showed that a granualar filter layer on sand can be an effective way to minimize base material erosion. Based on the physical model tests formulae were proposed for the sand erosion under wave loading, depending on filter thickness.
|Jaar van uitgave||2014|