Abstract: This paper focused on analyzing the vulnerability degree on debris flow hazards, which is affected by various environmental factors. The correlation degree between different influencing factors and debris flow disaster susceptibility were studied using grey correlation analysis based on the analysis and summary of the field survey results on influencing factors for debris flow hazards in different debris flow gullies of Nanyu in Zhouqu County, Gansu Province, China which included the “August 8” large debris flow disaster instance. The results show that the susceptibility of debris flow disaster is relatively similar for the factors such as bank slope, channel blockage, and scouring range, the slope gradient and length of channel, vegetation, drainage area, and population density, solid matter source and geological hazards points density. For the different gullies in the same area, the hazard level of the debris flow disaster is impacted significantly by the bank slope, the channel blockage, the scouring range, the slope gradient, and the channel length. The model can predict the vulnerability of debris flow and provide important information in the hazard prevention and control.

Key words: geological engineering, mud-rock flow hazards, grey correlation theory, susceptibility assessment