Development of a local scour prediction model clustered by soil class

Abstract

Several studies have been conducted to assess local scour formulas in order to select the most appropriate one. Confronted with the limits of the previous formulas, further studies have been performed to propose new local scour formulas. Generalizing a single scour formula, for all soil classes, seems approximate for such a complex phenomenon depending on several parameters and may eventually lead to considerable uncertainties in scour estimation. This study aims to propose several new scour formulas for different granulometric classes of the streambed by exploiting a large field database. The new scour formulas are based on multiple non-linear regression (MNLR) models. Supervised learning is used as an optimization tool to solve the hyper-parameters of each new equation by using the ‘Gradient Descent Algorithm’. The results show that the new formulas proposed in this study perform better than some other empirical formulas chosen for comparison. The results are presented as seven new formulas, as well as abacuses for the calculation of local scour by soil classes. HIGHLIGHTS Modeling of local scour with clustering the data by soil type.; Using a large database of local scour.; Statistical analysis of the scour phenomenon followed by a regression model optimized by the gradient descent algorithm.; Reduction scour parameters.; Proposal of abacuses for the scour calculation.;

Keywords

• bridge local scour
• new scour formulas
• scour estimate
• soil classification