Susceptibility Evaluation Of Geological Hazards In Zhen'an Section Of 345 National Highway

With the continuous improvement of infrastructure construction,especially highway construction,the mountain road network in China extends in all directions.The geological environment conditions along the Zhen'an section of National Highway 345 are complex and changeable,which determines that the highway construction in mountainous areas will encounter a lot of geological hazards.It has certain practical value and practical significance to carry out geological hazard susceptibility assessment of Zhenan section of National Highway345.In this paper,taking the range of 2km on both sides of the highway as the study area,on the basis of analyzing the geological environment conditions and summarizing the development characteristics and distribution law of geological hazards,11 indexes are selected to construct the evaluation index system.The prone zoning results of geological hazards in the study area are obtained by using random forest model(RF),and compared with the evaluation results of support vector machine model(SVM).The main contents are as follows:(1)There are many types and quantities of geological hazards in the study area,with a total of 139 geological hazards,mainly small-scale geological hazards.Among them,91 landslides developed,accounting for 65.47% of the total hazards,mainly shallow landslides;45collapses,accounting for 32.37% of the total hazards,mainly rock collapses;and 3 debris flows,accounting for 2.16% of the total hazards,belonging to valley debris flow;(2)Based on the analysis of the formation environmental conditions of geological hazards in the study area and the summary of the development characteristics and distribution law of geological hazards along the highway,finally,11 geological hazard evaluation indexes such as elevation,slope,slope aspect,plane curvature,section curvature,rock and soil type,distance from fault,annual precipitation,distance from river,normalized vegetation index and distance from road are selected.The corr function in Matlab software is used to analyze the Pearsoncorrelation of each index in the study area,and the evaluation index system of geological hazard vulnerability is established;(3)Random forest model and support vector machine model are used to evaluate the vulnerability of the study area,and the vulnerability evaluation indexes under different models are obtained,which are imported into ArcGIS software and divided into five grades.Finally,the geological hazard susceptibility zoning maps of the two models are generated;(4)Compared with the two models,the random forest model is more accurate and the density of geological disaster points is higher in extremely high and high risk areas.Among the evaluation indexes,the distance from the road has the greatest influence on the evaluation results of the two models.