Effect of granular shapes on entrainment mechanisms of debris flows: Preliminary study through physical modeling

Abstract

Debris flows are phenomena resulting from the movement of soil, rocks, and sediments on steep slopes. The mass of flows transports debris along the slope, increasing the flow's force and impacting structures, property, and living life within the affected area. Forecasting debris flow dynamics in both spatial and temporal contexts is challenging due to the complex interactions between solid and liquid phases during movement. This paper presents the results of a study on entrainment and depositional mechanisms using a laboratory-scale flume model. The setup includes a main flume with an adjustable slope and a secondary flume with a configurable flat surface. The study investigates the influence of several variables on the entrainment and depositional morphology of debris flows, including the shape of solid materials, the solid-to-liquid ratio, the moisture content of the mixture, and the presence of a channelized bed. The findings indicate that mixtures predominantly composed of gravel significantly affect erosion and transport mechanisms. In contrast, mixtures with a high sand content did not exhibit clear erosion behavior. Additionally, mixtures of dry granular materials combined with water showed more distinct behavior compared to dry samples. The results from this physical model will be used to calibrate a numerical model in subsequent research.