云南昆明东川区泥石流危险性评价

Risk Assessment of Debris Flow in Dongchuan Area,Kunming,Yunnan Province

根据泥石流危险度评价的五个层次：即泥石流灾害野外调查、泥石流暴发成因分析、危险度评价模型、灾害评价与减灾。根据泥石流的发生学原理,10个自然因子分别用于代表能量、物质和激发条件,以用于自然危险度评价,在评价时采用了权重模型和方根模型,野外泥石流调查资料用于模型检验,结果表明权重模型能更好进行自然危险度区划;4个社会经济发展水平代表性因子用于经济状况评价。二者复合后得到该区域综合危险度评价。根据综合危险度评价结果最重度危险区面积为133.7 km^2,79.0%的泥石流沟该区内;重度危险区面积580.6 km^2,19.8%的泥石流沟位于该区内;中度危险区面积723.9km^2,有1.2%的泥石流沟位于区内;安全区面积119.0 km^2,该区内无泥石流沟,表明分区结果符合实际泥石流分布。根据分区结果提出了该区内泥石流减灾方案。

Debris flow risk assessment can be divided into five levels/steps, i.e. the field survey, the background conditions analysis, the risk assessment, the evaluation of the situation of the hazard and the advise of the mitigation way. Ten factors, which represent the energy, the mass quantity and the trigging conditions of the debris flow, were put into the weight model and the square model to estimate the debris flow risk of nature backgrounds for the studying area. It has shown that the result of the weight model is better than that of the square model. Four factors, which represent the social and economy backgrounds, are used to evaluate the economic levels of the studying area. Then, we put them together to get the comprehensive risk assessment at last. The result has 4 levels. The most dangerous zone is about 133.7 km^2 and about 79.0% of the total debris flow gullies of the studying area are located in this zone; the serious dangerous zone is about 580.6 km^2 and it has 19.8% of the debris flow gullies; the middle（light） dangerous zone is about 723.9 km^2 and about 1.2% of the debris flow gullies are located in this zone; the safety area is about 119.0 km^2 and it has no debris flow gully. This result fits the field survey data fairly well, and it shows that the method used in this paper is reliable. Advice of mitigation way is also provided.