降雨特征与泥石流总量的关系分析

Relationship between rainfall characteristics and total amount of debris flow

利用云南东川国家泥石流野外观测站对蒋家沟30场泥石流的观测资料,通过对降雨观测数据和泥石流资料的分析,研究了降雨与泥石流总量的关系。将降雨指标分为间接前期雨量、直接前期雨量1、h雨量和过程雨量,并通过主成分分析、相关分析和数据拟合分析等数理统计方法,探讨不同雨量与泥石流总量的关系。结果发现:过程雨量和间接前期雨量对泥石流总量的贡献较大,其次是1 h雨量。过程雨量、降雨综合得分与泥石流总量的关系最为密切,相关系数分别为0.854和0.828;其次是间接前期雨量和1 h雨量,相关系数分别为0.414和0.360;直接前期雨量与泥石流总量的关系最差,相关系数仅为-0.013。同时,随着过程雨量和降雨综合得分的增大,泥石流总量也随之增加,但是在过程雨量小于15 mm及降雨综合得分小于0.1的情况下,泥石流总量随二者的增加而增加的幅度减缓,当过程雨量大于15 mm及降雨综合得分大于0.1时,泥石流总量随二者增加而增加的幅度加大,泥石流总量与二者之间具有指数关系。据此,该文提出在进行泥石流总量计算时,应考虑降雨特征因子,为建立合理的泥石流总量计算模型提供参考。

This paper mainly discusses the relationship between total amount of debris flow and rainfall based on the observation data of 30 debris flow events in Jiangjiagou Ravine, obtained by State Field Observation and Research Station of Debris Flow in Dongehuan, Yunnan Province, southwestern China. Considering the impact of rainfall on debris flow, the rainfall was classified into indirect antecedent rainfall, direct antecedent rainfall, 1 h antecedent rainfall and process rainfall, and then the relationship between rainfall characteristics and total amount of debris flow was researched by correlation analysis, principal component analysis and data fitting analysis using the data of 30 debris flow events and their corresponding rainfall. The results showed that process rainfall and indirect antecedent rainfall had more contribution to total amount of debris flow, and 1 h antecedent rainfall was inferior to them. Both process rainfall and rainfall integrated score had close correlations with total amount of debris flow, and the coefficients were 0. 854 and 0. 828, respectively. The correlation coefficients of indirect antecedent rainfall, 1 h antecedent rainfall and direct antecedent rainfall were lower, which were only 0.414,0. 360 and -0.013, respectively. Moreover, the higher the process rainfall and rainfall integrated score were, the greater the total amount of debris flow was. When process rainfall and rainfall integrated score were less than 15 mm and 0.1, total amount of debris flow increased slowly. While when they were more than 15 mm and 0.1, the total amount of debris flow increased quickly with exponential trend. It is concluded that rainfall characteristics should be considered in calculating total amount of debris flow, which is redounded to establish scientific mathematic model of total amount of debris flow.