Study On Regional Landslide Susceptibility Evaluation Based On Geological Conditions Classification Of Slope Units

Geological disaster investigation and risk assessment is the key work of geological disaster prevention,and regional landslide susceptibility evaluation is the basic work of geological disaster risk assessment.The selection of evaluation units in regional landslide susceptibility evaluation directly affects the rationality and accuracy of the evaluation results.At present,the evaluation units are mainly grid units and slope units.The extraction of slope units is based on the characteristics of topography and geomorphology,which cannot reflect the boundary characteristics of geological environment of landslide.Therefore,how to combine the characteristics of topography and geological environment boundary to extract the slope unit is a key problem that needs to be solved urgently.In view of this,this paper explores the method of dividing slope units based on geological conditions,establishes the evaluation index system of regional landslide susceptibility,conducts the research on regional landslide susceptibility evaluation,and thus constructs the regional landslide susceptibility evaluation system based on dividing slope units based on geological conditions.The main research work is as follows :(1)Research on slope element division method based on geological conditions.The strata dip map is obtained by interpolation of strata trend surface,and the slope direction map is obtained by surface analysis of DEM data.The two are superimposed to realize the classification of slope structure types.The boundary line is extracted based on the slope structure type to realize the slope unit division based on geological conditions.In order to compare and study the division effect of slope unit by geological condition method and slope unit by hydrological method,the area range,shape parameters and kernel density function are introduced to evaluate.Based on the evaluation results,it is found that the geological condition slope unit is better than the hydrological slope unit in terms of shape regularity and distribution uniformity.(2)The establishment of regional landslide susceptibility evaluation index system.Based on the existing research results,the Pearson correlation coefficient method and principal component analysis were introduced to the 20 evaluation factors of the preliminary screening,and the independence test and weight analysis were carried out.Finally,12 evaluation factors were determined,and the regional landslide susceptibility evaluation index system was established.Frequency ratio method was used to analyze the sensitivity of landslide induced by evaluation factors in different zones,and the grading standards of each evaluation factor were determined.(3)Study on classification rationality and model accuracy of regional landslide susceptibility evaluation.Based on the information model,support vector machine model,logistic regression model and BP neural network model,the slope unit of geological condition method and slope unit of hydrological method are used to evaluate the landslide susceptibility.Based on the evaluation results,the rationality of landslide susceptibility classification is compared and analyzed.In addition,the ROC curve was introduced to verify the accuracy of the regional landslide susceptibility evaluation model.It was found that the average AUC of the slope unit based on the four evaluation models was significantly better than that of the slope unit based on the hydrological method.The slope unit of geological condition method combined with support vector machine model has the best evaluation effect on regional landslide susceptibility.Based on the 12 evaluation factors and classification standards,the regional landslide susceptibility evaluation system of slope unit based on geological condition method combined with support vector machine model is constructed.(4)Applied research on landslide susceptibility evaluation in Fuling District based on slope unit of geological condition method.The slope unit of geological condition method is divided in Fuling District,and the evaluation index system proposed in this paper is used to evaluate the landslide susceptibility combined with the support vector machine model.