为了探索都江堰—汶川G213线宽缓窄陡泥石流的降雨阈值，利用地震前后的遥感影像及地理信息系统（geographic information system, GIS）技术，提取研究区43条沟的地形因子；基于主成分分析法和SPSS软件分析各因子的相关性，建立综合地形因子临界模型；通过引入降雨因素利用支持向量机分类模型得到不同沟道形态的降雨阈值模型。结果表明：综合地形因子以0.51为沟道形态分界线，大于0.51为窄陡型沟道，小于或等于0.51为宽缓型沟道，利用北川部分沟道进行模型验证，准确性达99%；基于综合地形因子所划分的沟道类型，通过研究区降雨数据进行数学分析得到综合地形因子和降雨因素之间的影响系数，利用随机向量机分类模型，对获得宽缓与窄陡沟道的降雨强度I和降雨历时D数据，建立I-D降雨阈值模型，I-D降雨阈值模型表明影响系数越大，地形因子就大，越利于泥石流的发生，激发泥石流所需的降雨阈值就越小，此类泥石流为窄陡型泥石流，反之亦然。研究成果可为不同区域、沟道类型、时间段的震后泥石流降雨阈值提供参考。

In order to explore the rainfall threshold of wide moderate narrow steep debris flow along the G213 line from Dujiangyan—Wenchuan. Remote sensing images before and after earthquakes and geographic information system (GIS) technology were used to establish a comprehensive terrain factor critical model, and topographic factors of 43 gullies in the study area were extracted. A comprehensive terrain factor critical model was established based on principal component analysis and SPSS software to analyze the correlation of various factors. By introducing rainfall factors and utilizing support vector machine classification models, rainfall threshold models for different channel shapes were obtained. The results show that when the comprehensive terrain factor is greater than 0.51, it is a narrow and steep channel. When it is less than or equal to 0.51, it is a wide and gentle channel. The model validation of some channels in Beichuan achieves an accuracy of 99%. Based on the classification of channel types based on comprehensive terrain factors, the influence coefficient between comprehensive terrain factors and rainfall factors is obtained through mathematical analysis of rainfall data in the study area. By obtaining the rainfall intensity I and the rainfall duration D, then utilize a random vector machine classification model was used to obtain I-D rainfall threshold models for wide and narrow steep channels. The I-D rainfall threshold model indicates that the larger the influence coefficient, the greater the terrain factor, which is more conducive to the occurrence of debris flows. The smaller the rainfall threshold requires to trigger debris flows, such as narrow and steep debris flows, and vice versa. The research results can provide reference for the post earthquake debris flow rainfall threshold in different regions, channel types, and time periods.