Development Characteristics And Risk Assessment Of Geological Hazards In Section S1 Of Lexi Expressway

Section S1 of The proposed Le(Shan)West(Chang)expressway starts from Yonghong Township,Mabian County and ends at Dagudui Village,Leibo County,with a total length of 40 km.The complex geological structure along the highway,collapse,landslide,debris flow and other geological disasters occur frequently,which pose a great threat to the construction and operation safety of the highway.Based on the geological environment conditions and geological hazards development based on investigation of through the characteristics and different types of slope deformation and destruction mechanism in the study area analysis,combined with the analysis of typical geological disaster,master the general rules of the development of geological disasters in the study area and on this basis,combining with geological disasters influencing factors were analyzed,and the selection of suitable evaluation factor,adopting ahp fuzzy comprehensive evaluation method to risk assessment of the study area,through the platform of Arc GIS,risk zoning maps in the study area respectively,and combining the highway design,the geological disaster prevention and cure Suggestions are put forward.The research results provide a scientific basis for the planning,design and disaster prevention and reduction of The highway route in Lesi,and have a certain theoretical significance for the regional geological disaster evaluation research of the highway.The main research results are as follows.(1)Analyze the geological environment conditions of the study area by collecting relevant geological data and field investigation.And according to the landform,stratum lithology combination and the different engineering geological conditions,could be divided into three types of rock and soil body rock groups,respectively,hard rock(?),half hard rock group(?),loose rock group(?).(2)the slope in the study area is classified into two types of rock slope and soil slope,according to the rock to the relationship between highway to the point of intersection,the slope in the study area can be divided into consequent slope,reverse slope and transverse slope,oblique slope,according to the different further divided slope rock strata dip Angle structure types,analyzes the different kinds of deformation failure mode and stability of the slope,mastered the general law of slope deformation and failure in the study area.The main failure modes of slope are slip-pull-crack and slip-bend.The soil slopes are dominated by landslides and debris flow deposits,followed by collapse deposits and less alluvial-diluvial slopes.The main failure modes are interfacial sliding and circular sliding.(3)A total of 34 geological disasters were investigated along the highway,including 12 landslides,8 collapses and 14 debris flows.Statistics were conducted on different disaster types and basic characteristics,and typical disaster points wereselected for stability analysis.Based on the analysis of the development characteristics and basic influencing factors of geological hazards along highways,the distribution rules are summarized,and the failure modes of slopes in the study area are combined.Six evaluation factors including slope,elevation,engineering rock group,slope structure,water system distance and rainfall are selected to establish the risk evaluation index system of geological hazards in the study area.On this basis,the evaluation factor is quantified and the weight of each factor is determined by analytic hierarchy process.(4)the study area according to the size of 19 m * 19 m square grid,divided into463286 grid unit,using Arc GIS software to map the raster map each evaluation factor,the fuzzy comprehensive evaluation method of each evaluation factor dangerous hierarchies,for different evaluation factors by membership functions,and in Arc GIS to calculate each evaluation factor of high,medium and low membership figure,finally using Arc GIS weighted superposition of geological disasters in the study area risk zoning map,and the evaluation results by the ROC curve test,Finally combined with the dangerous zoning map and the actual situation of the project to put forward the corresponding prevention and control Suggestions for highway geological disaster.