泥石流流域形態特徵

Characteristics and Distributions of Debris-Flow Basin

李泳(Yong Li) ； 胡凱衡(Kai-Heng Hu) ； 崔鵬(Peng Cui) ； 陳曉清(Xiao-Qing Chen)

《中華水土保持學報》 33卷3期 (2002/09) Pp. 233-240

https://doi.org/10.29417/JCSWC.200209_33(3).0007

摘要

中國近6000個泥石流流域的統計表明，流域形態特徵如流域面積、溝長、比降、切割度等，均服從統一形式的分佈，即廣義的指數型分佈。文中以Weibull、Gamma分佈爲例對諸多特徵量進行擬合，分佈之區域差別，大抵表現在分佈參數的不同：相似的概率分佈説明諸因數對泥石流發生的影響不在大小本身，而在於相對的概率意義。對蔣家溝流域源地分支小流域所做相同統計工作，證明小尺度流域的分佈也完全是相似的。結合泥石流規模的分佈，可以發現泥石流的規模-頻率關係跟泥石流發生於流域源地小分支流域的事實，有著統計上的一致性。這樣，區域和單個流域的統計規律竟與泥石流本身的規律聯繫起來了。

關鍵字

泥石流 ； 流域形態特徵 ； 分佈 ； 概率

並列摘要

Statistical studies of 6,000 debris-flow basins collected from China show that planimetric characteristics of the basin, such as drainage area, mainstream length, channel gradient, dissection, are exclusively subjected to probability distribution in a general exponential form. Weibull distribution and Gamma distribution have been taken as special cases to fit these factors, and the distinction in distributional parameter reflects the locality of the basins. It follows that impact of planimetry of basin on debris flow occurrences makes sense only in comparison, say, between various regions, and the absolute value loses its fundamental means. Relative potentiality of occurrence of debris flow for each factor can be derived from the conditional probability of the distribution. The same statistics on the unique debris-flow basin, Jiangjiagou Gully in Yunnan, reveal distributional law to be the same as the regional results. Combined with the magnitude-frequency relation of debris flow, these distributional laws find their implications pertaining to the fact that debris flow does originate in the source tributaries in a basin. Thus, distribution in regional basins and in a certain basin is consistent with the observational fact of occurrences of debris flow.

並列關鍵字

debris flow ； basin characteristics ； distribution ； probability