A new framework for modeling sediment fining during transport with fragmentation and abrasion

Abstract

A new framework for modeling sediment fining during transport is proposed. The model is based on a physical description of both abrasion and fragmentation processes. It attempts to describe and explain the changes in the grain-size distribution of sediments during their transport in a water flow. Abrasion and fragmentation are modeled through the use of breakage frequency functions and daughter size distributions. These functions are determined experimentally for the specific case study which is presented. Comparison between the predictions from the model and experimental data from the case study show that 1)both abrasion and fragmentation are involved in the degradation 2)fragmentation eciency decreases during the experiment 3)the shape of the pebbles provides feedback between abrasion and fragmentation. This type of model is therefore appropriate for explaining degradation mechanisms, which is promising for a future application to rivers.