Author(s): Boriss Gjunsburgs; Elena Govsha; Gints Jaudzems
Linked Author(s): Boriss Gjunsburgs
Keywords: River bed; Scour; Stratification; Flow; Development in time
Abstract: River bed stratification influence on the scour depth value near bridge foundations, considerably increasing or reducing it - depending on sequence, thickness of layers with different grain sizes and can be reason of the bridge failure. The aim of this study is to elucidate the influence of the bed stratification on the scour depth at elliptical guide banks for clear water conditions on the plain rivers. New methods for computing the depth of scour development in time and equilibrium stage of scour at elliptical guide banks under layered bed are presented. The influence of the river bed stratification on the scour depth near elliptical guide banks is confirmed by presented results. The depth of scour, for example, is always greater when a fine-sand layer is under a coarse-sand layer (s), compare with the depth of scour obtained with mean grain size diameter of coarse-sand layer, which is on the top. The calculation of the scour depth near bridge foundations by using only the grain size diameter which is on the top of the river bed and neglecting the layering, as it accepted now, can lead to wrong results and finally to considerable damages and losses.
Year: 2013