Geological Disaster Characteristics And Risk Assessment In Guangfeng District,shangrao City,jiangxi Province

Guangfeng District,Shangrao City,Jiangxi Province,is a hilly area in the south of the Yangtze River.The overall terrain is high in the southeast and low in the northwest.The tectonics in the area is complex,the terrain fluctuates greatly,the rock mass is broken,and human engineering activities are intense and rainfall is abundant.As a result,geological disasters occur frequently in the whole area,posing a serious threat to the safety of people’s lives and property.This article takes Guangfeng District as the research object,summarizes and analyzes the characteristics and distribution patterns of geological disasters based on regional geological environment and field survey data,and explores the relationship between geological disasters and geological environment.The analytic hierarchy process-information quantity method is selected for risk assessment,and the fuzzy comprehensive evaluation method is selected for vulnerability assessment.Based on the spatial analysis function of Arc GIS,the risk assessment of geological disasters in Guangfeng District is conducted and prevention suggestions are proposed.The main research contents and results are as follows:(1)The geological hazards in the study area are relatively developed,mainly including landslides,collapses,hidden dangers of landslides and collapses.There are 568 geological hazard points in total,including 227 landslides,22 collapses,3 debris flows,4 ground collapses,207 landslide hazards,and 105 collapse hazards.Among them,the distribution of landslides,collapses,landslide hazards,and collapse hazards is relatively scattered,and the overall scale and grade are relatively small.The impact of rainfall on time has a periodic characteristic.Generally speaking,most geological disasters occur in soft rock areas with steep slopes,relatively fractured rock masses,and intense human engineering activities.Debris flows are mainly distributed in the northeast and east of the study area,while surface subsidence is mainly distributed in the central and western parts of the study area,with a small number and low scale.(2)By discussing the relationship between geological environment conditions and geological disasters,it is concluded that the regional geological disasters are mainly controlled by the special stratum lithology and tectonics of Guangfeng District.The geological disasters are mainly distributed in the hilly landform of denudation and erosion structure.The natural slope is 0～15 °,the elevation is between 100～200m,the elevation variation coefficient is greater than 0.03,and the lithology is relatively hard clastic rock,limestone and metamorphic rock rock group,within 400 m from the fault,Areas within 200 m of the river,with an average annual rainfall value of 1546-1748 mm,and areas within 200 m of the road.(3)Using terrain type,natural slope,coefficient of elevation variation,engineering geological rock formations,fault buffer zone,river buffer zone,average annual rainfall,and road buffer zone as evaluation factors,a comprehensive evaluation model was constructed using the analytic hierarchy process-information quantity method to complete the geological hazard risk assessment of Guangfeng District.The results indicate that Guangfeng is divided into extremely high risk areas,high risk areas,medium risk areas,and low risk areas,with an area proportion of 23.66%,32.03%,27.10%,and 17.2%,respectively.The evaluation model is based on the subject curve,with an AUC value of 0.786,demonstrating good accuracy of the constructed evaluation model.(4)Based on socio-economic data,the vulnerability assessment of Guangfeng District is completed using the fuzzy comprehensive evaluation method.According to the empirical formula “risk=danger × Vulnerability”,completing the risk assessment of geological disasters in Guangfeng District.The results show that Guangfeng District is divided into extremely high risk areas,high risk areas,medium risk areas,and low risk areas,with an area proportion of6.45%,27.26%,35.81%,and 30.49%,respectively.The overall geological hazard risk in Guangfeng District is moderate to high,with a spatial distribution characterized by high in the northwest and low in the southeast.