Abstract:

Beibei district in Chongqing City is the primary area where debris flow hazard always occurred, and the outbreaks of debris flows are controlled by the rainfall, material source conditions, geographical conditions，geological structure, valley characteristics, vegetation and other internal or external factors. In this paper, in order to evaluate effectively the outbreak risk of debris flows in Beibei district, according to many factors of debris flows outbreak, and based on the method of factor analysis，massive data of 30 typical debris flows was analyzed, and the three main factors of debris flow were classified, which contains topography and material source conditions, vegetation coverage, maximum rainfall. And then, the clustering analysis about main factors score was carried out by the fast clustering method. Meanwhile, the outbreaks danger degree of debris flow hazard was determined. The evaluation results were consistent with the actual occurrence of these debris flows in Beibei district of Chongqing City, which show that one debris flow is extremely risk, three debris flows are high risk, twenty-one debris flows are moderate risk, and five debris flows are low risk.

Key words:  debris flow hazard, factor analysis, clustering analysis, risk assessment, Beibei district, Chongqing