Abstract:The Changbai Mountain Tianchi Scenic Area is threatened by a number of debris flow ditches. In order to reduce the losses and threats caused by mudslides, the rainfall process of debris flow disasters in each ditch is analyzed by collecting and sorting the debris flow activity data and corresponding rainfall data in the area, and obtaining Changbai Mountain. The debris flow in Tianchi area stimulates the characteristics of rain patterns, and studies the relationship between relevant rainfall parameters (hour rainfall intensity, historical accumulated rainfall, pre-effective rainfall and rainfall duration) and debris flow disasters, and obtains the criticality of debris flow disasters in Tianchi area of Changbai Mountain. Rainfall value. The research shows that the debris flow induced by the debris flow in the Tianchi area of Changbai Mountain is divided into long-term continuous rainfall and long-term rainfall. The long-term continuous rainfall type has long duration of uninterrupted rainfall, and the total rainfall time also lasts longer. The debris flow gradually reaches the rainfall intensity. Outbreaks at critical values. Long-term rainfall is longer than total long-term rainfall. The rainfall intensity of this rainfall type has a repeated process of increasing from zero to the maximum value and then decreasing until the final loose bulk is saturated to a critical value, resulting in a debris flow outbreak. According to statistics and analysis, the rainfall prevention and early warning indicators (critical rainfall) of the debris flow disaster in the Tianchi area of Changbai Mountain can be used as the prevention value with the historical accumulated rainfall of 43.5mm or the previous effective rainfall of 32.7mm. The hourly rainfall intensity is 19.7mm/h. As a critical rainfall of debris flow, the study of different types of induced rain patterns and critical rainfall can provide a scientific basis for monitoring and warning of debris flow disasters in the Tianchi area of Changbai Mountain.