| Jinsha River is famous for its rich water resources at home and abroad. Jinsha River’s riverbed is narrow and its Bank slope is steep. The overall look is a "V" shaped bed which with "high,deep,narrow,curved,steep" characteristics.The river way’s type is a typical mountain valley type. Ningnan small watershed is in the middle of the Jinsha River. Ningnan and Qiaojia County are respectively in jinsha river on both sides whose area is about 100km~2.This area is a towns and villages concentrated area where the population distribution is concentrated and the population density is large.What’s more,Its engineering construction and other important infrastructure are concentrated and the social economy developed. In recent years,with the development of the western region to continue,human social and economic activities are more frequent which make great influence on the regional geological environment. Such as the strong human engineering activities,the rich surface water and groundwater and the serious gully erosion. The impact on the natural geological environment of human is very outstanding.And it is prone to landslide,collapse,debris flow and other geological disasters.This article through the early stage of the interior data collection and field survey to obtain the types of distribution and development of geological disasters in the study area. Through the analysis of the geological disasters in the study area,we found factors which are associated with the development of geological disasters are mainly: slope,slope height,slope type,engineering geological petrofabric,geological structure,human engineering activities and rainfall.During the risk assessment in the studied area,we use the amount of information method and the BP artificial neural network.Through Arc GIS platform,we use DEM figure in the study area respectively to extract the slope,slope height,slope,engineering geological petrofabric,geological structure,human engineering activity and rainfall this seven evaluation index data;and we use two methods of evaluation model to evaluate. Finally, by the ROC curve and AUC value comparison,we find that the result from BP artificial neural network method is more accurate.Vulnerability analysis is the relationship between the intensity of the disaster and hazard affected loss of complex research. In this paper,we use fuzzy comprehensive evaluation method for vulnerability assessment in the studied area.Considering the basic data availability and according to the Research area bearing complex characteristics,the study selected the township population density(people / km~2),housing density(km~2 / km~2) and road lines major survey area included density(km / km~2) evaluation these three factors to establish a vulnerability assessment index system,finally obtained the vulnerability assessment results of the survey area. Geological disaster risk assessment is a process which is use risk and vulnerability through a method similar to take operations in mathematics to obtain the geological disaster risk. Geological disaster risk zoning map is based on the degree of geological disaster risk zoning map and the geological disaster vulnerability zoning map,using risk evaluation principle of superposition for geological hazard risk evaluation and finally the risk in the study area is divided into higher risk area, high risk area,the medium risk area,low risk area and lower risk area. The area were 3km~2,14km~2,26km~2,35km~2,22km~2. |
PDF Full Text Request