| The impact factors of the susceptibility assessment of debris flow disaster in the study area were put forward through the quantitative analysis of engineering geology and other factors and the influence of engineering geology on debris flow disaster in the research area.In this article,susceptibility evaluation of debris flow in the study area is based on analytic hierarchy process and information model and fractal theory,and using ArcGIS spatial analysis technology,the small watershed unit is used to classify the susceptibility of the study area,which was provided a reliable basis for the prevention and control of debris flows in Bailang county.The main content of this article is as follows:(1)By collecting geological disaster data in Bailang County,the geological conditions of debris flow disaster in the study area have been found out,and the types and distribution rules of the debris flow disaster development in Bailang county are summarized:(1)there are 167 debris flows in Bailang county;(2)all of the debris flows belong to rainfall type debris flow;(3)it is mainly small debris flow;(4)mainly concentrated in the valley area on both sides of the valley;(5)it is controlled by the season and is concentrated in the rainy season of 6~9 months.(2)On the platform of ArcGIS,9 kinds of evaluation factor model of engineering rock group,slope,elevation,rainfall,fault zone buffer zone,water system density,landform,human activity density and disaster point density is established on the basis of geological hazard survey and disaster records.According to the GIS spatial analysis function,the 25 m x 25 m grid unit is selected,each factor is quantified,the sub basin unit is extracted and the sub basin is used as the prone division unit,thus the prone evaluation system is constructed.(3)According to the information quantity model,the information value of each evaluation factor is calculated,the amount of information is assigned to each evaluation factor by GIS,the total information value is calculated by grid analysis tool,and the total information value of debris flow disaster in the study area is reclassified by sub-basin division unit,and the distribution map of debris flow in brandy county is obtained.(4)According to the analytic hierarchy process(AHP),the evaluation factor discriminant matrix is constructed and the consistency check is carried out.The weight of each evaluation factor is calculated by the test qualified discriminant matrix,and the importance degree is assigned to the different classification of the evaluation factors On the platform of GIS,the data of the evaluation factor grid grid is normalized and the final profit is made.A grid calculator is used to superimpose the normalization of the evaluation factors,and the debris flow disaster prone grades in the study area are divided into sub-basin units.(5)Fractal theory is used to calculate the variable dimension characteristics of evaluation factors and debris flow disaster distribution.The reciprocal of the fractal dimension is used as the evaluation factor weight,and the product of the evaluation factor and the information value in each state segment is used as the index of susceptibility within the segmented region.Finally,the vulnerability index of debris flow is calculated and the vulnerability grade of debris flow is classified.(6)The results of the evaluation of the three models were tested by the ROC curve.The prediction of the three models were all high,and the differences and advantages of the results were analyzed and compared by the analysis of the three models. |
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