Validation and Optimization of a Design Formula for Stable Geometrically Open Filter Structures

Granular filters are used for protection against scour and erosion of base material. For a proper functioning it is necessary that at the interfaces between the filter structure, the subsoil and the water flowing above the filter structure no material will be transported. Different types of granular filters can be distinguished, this paper...

Falling aprons at circular piers under currents

Traditional guidelines on rock protection at circular piers predominantly focus on preventing shear failure (by choosing a sufficiently large rock size), winnowing failure (by designing an appropriate filter) and edge failure (by selecting a sufficient extent). In particular areas (e.g. in an eroding river channel or in an area with large-scale...

Interface stability of granular filter structures under currents

Granular filters are used for protection of structures against scour and erosion. For a proper functioning it is necessary that the interfaces between the filter structure, the subsoil and the water flowing above the filter structure are stable. Stability means that there is no transport of subsoil material through the filter to the water above...

Interface stability of granular filter structures: Desk study

A desk study has been carried out regarding interface stability of granular filter structures. Actually, the project focuses on two particular aspects: (1) interface stability as function of the thickness of the filter layer consisting of standard armourstone gradings, and (2) interface stability of gravel mixtures with a wide gradation The...

Rekenregels steenbestortingen: Stromingsbelasting en transportmodel: aanvullende werkzaamheden op VOP 2000, steenstabiliteit

Design formulas for granular filters

Shear stress concept in granular filters

Scour is a natural phenomenon caused by the flow of water in rivers and streams and occurs as a part of the morphological changes caused by rivers or as a result of man-made structures. For the Dutch Delta Works hydraulic structures were often constructed on fines with loose packing. To guarantee the geotechnical stability of these structures...

Analysis and prediction potential of new design formulas for granular filters

Evaluation of recent desk study results on granular filters

Recently, a number of desk studies have been carried out with respect to the phenomena in and the design of granular filters. These have resulted in some formulas allowing the dimensioning of granular filters. The most important formulas are those developed by Hoffmans based on the shear stress concept of Grass (indicated hereafter as the...

Evaluation of recent desk study results on granular filters

Stroming in granulaire filters: Oriënterende experimenten

Haalbaarheidsstudie naar het meten van de demping van drukfluctuaties in filterconstructies