Erosion Behavior of Sand?Silt Mixtures: Revisiting the Erosion Threshold

The erosion threshold, beyond which bed sediments start to move, is a key parameter describing sediment transport processes. For silt-dominated mixtures, in the grain size between sand and clay, existing experimental studies exhibit contradictory observations. That is, was either sand-like or clay-like, suggesting transitional behavior. To explore underlying mechanism of behavior silt-sized sediment, we revisited topic threshold sand-silt mixtures by carrying out series experiments for different compositions. results suggest that there exists critical silt content approximately 35%, separating two domains. Below this value, shear stress follows Shields criterion, whereas above mixed increases abruptly remains relatively constant with further increase content. By combining data, found proposed acts as tipping point, shifts from sand-dominated domain. domain, stable skeleton can be formed attraction forces resist erosion. However, are too weak form when small. Based on finding, modified formula better agreement data (an averaged bias 10%), performing than formulas (larger 30%).