Author(s): B. Gjunsburgs; E. Govsha

Linked Author(s): Boriss Gjunsburgs

Keywords: No Keywords

Abstract: One of the reasons for failure of engineering structures due to scour near the foundations is stratification of the river bed. Although the problem is very topical, the scour in the stratified bed conditions has not yet been investigated sufficiently well. In the present study, the scour at abutments and elliptical and straight guide banks with a stratified bed under steady and clear-water conditions was investigated. Tests were carried out with uniform sands, standard deviation, and with two layers of different grain sizes and different sequence and thickness. A new method for computing the scour development in time at elliptical guide banks under stratified bed conditions is presented. The method is confirmed by tests results. Stratification of the river bed considerably affects the value of scour depth near the foundations. According to the results obtained in test sand by the method presented, the depth of scour is always greater when a fine-sand layer is under a coarsesand layer (s). Using for calculations of scour depth the grain size on the top of the river bed and neglecting stratification can lead to wrong results and possible damages and losses.

DOI:

Year: 2012