Geological Hazard Susceptibility And Risk Assessment In Linwei Area Based On GIS

Linwei District of Weinan City is located in the eastern part of Guanzhong Plain,Shaanxi Province.The gullies and plateau are scattered vertically and horizontally,and the geological hazards are well developed.According to the investigation and statistics,there are 83 geological hazards in Linwei area,including 39 landslides,32 collapses,4 debris flows,7 ground collapses and 1 ground fissure.These geological hazards pose a great threat to the lives and property of the local people.Evaluating the susceptibility and risk of geological hazards in Linwei District is helpful to prevent geological hazards in the future,and has important practical application value in the prevention and control of geological hazards in Linwei District.Through field geological survey,statistics of types and quantities of geological hazards in the area,analysis of the characteristics of the development of geological hazards,combined with local actual geological environment conditions,selection of qualitative and quantitative evaluation methods to evaluate the susceptibility and risk of geological hazards in the area,and finally carry out geological hazard prevention and control zoning in Linwei District.The research has achieved the following results:(1)Geological hazards in Linwei area are classified and counted,and their distribution regularity is revealed.It is shown as follows: geological hazards concentrate in strips along both sides of the valley;from south to north,the distribution density of geological hazards decreases gradually and the activity weakens;most of the hazards in the area are distributed in the middle and late Pleistocene aeolian loess;and a large number of collapse hazards are developed in the fault tectonic belt.(2)According to the formation conditions of geological hazards and the induced factors of geological hazards,the geotechnical structure,slope gradient,slope type,slope height,vegetation,rainfall and human engineering activities are selected as the evaluation indexes,and the evaluation index system of geological hazards susceptibility in Linwei District is established.Slope unit is selected as evaluation unit,and each index is quantified.Using information overlay method as evaluation model,the region is divided into four levels: nonprone,low-prone,medium-prone and high-prone.(3)Similar to the process of susceptibility assessment,the evaluation index system of geological hazard risk was established and the risk assessment of geological hazards in Linwei District was carried out.Linwei is divided into four levels: high-risk area,mediumrisk area,low-risk area and extremely low-risk area.(4)Finally,the comprehensive evaluation method is used to divide the geological hazard prevention and control zoning.Linwei is divided into key control area,sub-key control area and general control area.