Abstract:
Debris flows on slope faces represent a common geological hazard. The initial movement mode and resource characteristics significantly impact the movement process of the debris flow. Based on a typical case of debris flows on slope faces at Dali west railway station of the Dali -Ruili railway, a series of laboratory scaled model tests were conducted to investigate the movement characteristics of these debris flows. A total of eight sets of tests were performed, including start movement modes such as planar and landslide-type slides, as well as varying viscosity, particle gradation, and volume of the resources. The results reveal three typical formation stages of debris flows: a startup stage with progressively increasing velocity, a movement stage with slightly decreasing velocity, and an accumulation stage with rapidly reduced velocity. The start velocity of loose resources is higher than that of dense resources, and the movement velocity decreases nonlinearly with distance. The scrapping effect on the slope face is pronounced in the mid-upslope zone, with a maximum scrapping depth reaching 60% of the surface layer thickness in the slope model. Accumulated soils near the slope toe exhibit sorting characteristics along the rush distance, with fine particles accumulating further away from the slope toe. Based on the test results, it is suggested that three or two zones along the slope face can be divided to prevent the debris flow according to the height of the resources position. The principle for the former is to restrict the start velocity at the upslope and reduce the scrapping effect on the slope face, and the principle for the latter is to decrease the start velocity of the resources and construct strong retaining walls at the slope toe.