Discriminance of the Possibility of Debris-Flow Blocked the Main River by Grey Correlation Degree - A Case Study on the Upper Reaches of the Min River

Intensity and range of damage caused by debris-flow which blocks up river are much larger than debris-flow which doesn´t block up river, study of this type of debris-flow may provide reference for evaluation, region partition of degree of risk, prevention and cure and etc of debris-flow disaster, and possesses important significance in practice of disaster mitigation and prevention. Grey correlation degree analysis, a potent tool for disposal of uncertain system of small sample or poor information, is applied to analyze possibility of river block by debris-flow in this paper, and four debris-flow ravines of river-block type, each two debris-flow ravines of block type and non-block type at upper reaches of the Min River are selected as sample. A typical debris-flow ravine of river-block type is selected with its characteristic parameter as canonical sequence, degree of association between characteristic parameter and canonical sequence of other sample of debris-flow ravine is calculated. The result manifests basically that the higher degree of river block by debris-flow ravine, the more grey correlation degree with canonical sequence, therefore possibility of river block by debris-flow can be analyzed by grey correlation degree.