Engineering Geological Characteristics And Zoning Evaluation Of The Deep-cut Canyon Area In The Middle Reaches Of Lancang River

The deep-cut canyon in the middle reaches of the Lancang River is located on the southeastern edge of the Qinghai-Tibet Plateau.It is the axis of the entire ChangduSimao block and the core area of the parallel flow of the three rivers.With its complicated geological environment conditions and the follow-up of various basic engineering constructions in recent years,it is very necessary and urgent to carry out research on engineering geological characteristics in this area.In view of this,on the basis of the research topic of "Evolution Law and Stability Evaluation Index System of Geological Environment in Deep-cut Canyon Area",this paper conducted a singlefactor feature zoning study on various engineering geological conditions with deep cut gorge in the middle reaches of Lancang River as the research object.Combined with the characteristics of the canyon,the morphological types and engineering geological characteristics were preliminarily discussed.Subsequently,a statistical analysis of the main controlling factors and a susceptibility zoning study on the phenomenon of frequent occurrence of geological disasters in the deep-cut canyon area.Finally,the comprehensive engineering geological zoning evaluation based on GIS was carried out in the deep-cut canyon area in the middle reaches of the Lancang River.The main research progress are:(1)The regional geological background information was collected and sorted in detail to obtain the meteorological and hydrological statistical information of each district and county,and the corresponding regionalization of the regional topography,stratum construction and structural units.Based on the analysis of neotectonic movement,the historical seismic information is counted,which lays the foundation for the subsequent single factor analysis of engineering geological characteristics;(2)A single-factor feature analysis was conducted on the influencing factors of engineering geological features in the study area,and a preliminary grid map of each single-factor was obtained.It focuses on the analysis of the morphology of the canyon geomorphology,and combines the morphological parameters of Hack and SL to divide the steep section of the river.Then summarize and summarize its morphological types and characteristics;(3)Perform qualitative geological analysis on the main controlling factors of typical geological disasters,and conduct detailed statistical analysis on the influencing factors of various geological disasters.It is found that the development and distribution of geological hazards are closely related to the deep-cut canyon area.Through the calculation of information value and the weight calculated by entropy weight method,the distribution of geological hazards is mainly controlled by factors such as earthquake,slope,fracture,road,water system,rainfall and so on.The susceptibility zoning results show that: geological hazards are high and middle-prone areas account for 40.9% of the total area,but 91.21% of geological hazards are developed,and they are mainly distributed within 3 km of both sides of the main stream of the deep-cut valley of the Lancang River.In addition,the asymmetrical V-shaped river valley is a river valley with high incidence of disasters;(4)On the basis of grid partition maps of single-factor engineering geological conditions,select terrain slope,engineering geological rock group,different geological structure influence range,peak seismic acceleration,geological disaster susceptibility zoning,hydrogeological conditions,terrain speed The 8 influencing factors of rate and annual average rainfall constitute the evaluation index system of engineering geological zoning in the study area.The calculation of the combined weights shows that the three influencing factors of fault structure,engineering rock group and topography and landform have the largest weight.Based on the combination of GIS and combined weights,the grading and zoning evaluation of engineering geological conditions was carried out in the study area.Finally,the engineering geological characteristics of each river section and each valley type are summarized and summarized,and the results of the engineering geological evaluation of the zone-segment-divided valley type are obtained.The research ideas and technical methods adopted in this paper have a certain reference significance for the study of deep-cut canyons in other watersheds.The zoning results provide a certain reference for the follow-up engineering survey and engineering construction suitability evaluation.