区域泥石流危险度评价研究进展  

Advance in research on assessment for degree of regional debris flow hazard

作　　者：刘希林[1] 

机构地区：[1]中国科学院成都山地灾害与环境研究所,四川成都610041

出　　处：《中国地质灾害与防治学报》2002年第4期1-9,共9页The Chinese Journal of Geological Hazard and Control

基　　金：国家自然科学基金资助项目(49771004)

摘　　要：评述了自20世纪80年代末我国开展泥石流危险度评价研究以来,两个主要不同时期的区域泥石流危险度评价方法及其发展过程。详述了我国现行的区域泥石流危险度评价技术及其改进的评价因子转换赋值新方法。现行的区域泥石流危险度评价方法于1995年提出,是以不同的行政区划为基本单元来进行的。评价因子包括主要因子泥石流分布密度,次要因子岩石风化程度系数、断裂带密度、≥25°坡地面积百分比、洪灾发生频率、月降雨量变差系数、年雨量平均≥25mm大雨日数和坡度≥25°坡耕地面积百分比。区域泥石流危险度表达为以上8个因子极差变换后的赋值与其相应的权重乘积之和。这一评价公式,加强了主要因子的作用。主要因子的权重系数上升到33%时则使区域泥石流危险度评价可用一个简单的数学公式来表达。得出的危险度数值已经标准化,取值范围介于0～1之间。这一评价方法的不足之处是得出的危险度数值只有相对意义而不具有绝对意义。在最新的区域泥石流危险度评价研究中,通过分段函数赋值的新方法克服了上述不足。分段函数赋值是基于以下的假定:当评价因子超过和等于某一上限值时赋值为1;等于下限值时赋值为0;处于中间值的赋值为0 5。以这3个数值为控制点,假定在每2个点之间,赋值呈线性变化。当中间点为上。This paper has reviewed two assessing methods for regional debris flow hazard developed in two different stages since the end of the 1980′s in China,and the technique currently used and its newest development are presented in detail.\;Present assessing technique was proposed in 1995,which is based on the administrative regions as the basic assessing units.Assessing factors include debris flow spatial density,degree of weathering of rock,active fault density,percentage of slope greater than 25 degrees of the total,frequency of flooding hazards,average covariance of monthly precipitation,average days with rainfall greater than and equal to 25mm by ten years,and percentage of cultivated slope greater than 25 degrees of the total.Regional debris flow hazard assessment is expressed as a sum of the products of the normalized eight factors and their weights.This assessing formula has emphasized the leading factor,debris flow spatial density,whose weight has been raised to 33%.Meanwhile the assessment has been simply expressed as a mathematical equation.Moreover the values of the hazard degree have been standardized between 0 and 1,which is consistent with the degrees of the vulnerability and risk of debris flow.\;The inadequacy of the present assessing method is that their hazard values are only relative values which cannot be compared each other from one region to another.The newest research on regional debris flow risk overcomes this problem.The transformation functions are based on the following regulation.Having determined the upper limit value and the mean value for each factor,the factor can be transformed by taking the upper limit value,the mean value,and the zero as the control points,and the three points are transformed to 1,0\^5,and 0,respectively.It is assumed that the transformed factors vary linearly between the control points.Therefore,each factor can be represented by linear or bilinear model.Based on the statistical data in southwestern China,we estimated the upper limit value,and the mean value for ea

关 键 词：泥石流 危险度 区域评价 

分 类 号：P642.23[天文地球—工程地质学]