Shear stress concept in granular filters
More Info
expand_more
Abstract
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 the bed in their immediate vicinity had to be protected. Though several types of bed protection can be distinguished, for example concrete blocks, asphalt, and granular filters (with or without geotextiles) the scope of this paper is limited to granular filters. In the Netherlands geometrically sand-tight filters are usually used. The stability of these filters is mainly determined by the geometrical properties of the materials. Consequently, these classical filters with numerous layers are very expensive. In this study a model relation for sizing a geometrically open granular filter is discussed. Our goal is to promote discussion than rather to try to solve the many problems in the complex field of filtration in geotechnical engineering.