Sediment transport for nonuniform sediment mixtures: the Egiazaroff equation

Código

XXIII-SBRH1212

Autores

Maurício Andrades Paixão, Masato Kobiyama

Tema

06 - Hidrossedimentologia

Resumo

Understanding the sediment production and transport is one of the major topics of hydrosedimentology today. Although there are several methods to evaluate the incipient movement, the Shields model is the most used. However, the model proposed by Shields assume that the sediments are uniform in an homogeneous and non-cohesive mixture. As such conditions are not easily found in nature, Egiazaroff proposed a sheltering coefficient, which considers the sediments in a non-homogeneous mixture in a wide range of granulometry. This coefficient allows to correct the Shields critical shear stress for nonuniform mixtures and can be used in mountain rivers, where the sediment size varies in several orders of magnitude. The equation proposed by Egiazaroff has been neglected for so many years in Brazil, and it is not mentioned in hydraulics or hidrosedimentology books . Thus, the present paper aimed to introduce the model proposed by Egizaraforr and recommend its use in mountain rivers in Brazil.