| Qinglongxia Scenic Area is located in the main ridge of the southern section of Taihang Mountain,Huguan County,Shanxi Province.It is a national 4A-level scenic spot with an annual reception of about 450,000 people.Tourism is a pillar industry for local residents to get rich and increase income.At the same time,the canyon scenic area has steep mountains,developed faults,and rock fragmentation,and thusit is an area with a high incidence of geological disasters,which affects the operation and development of tourism in this area.This paper divides the Qinglong Gorge scenic spot into 4 geological disaster risk grade areas,aiming at providing technical basis for disaster prevention and mitigation in the scenic spot,protecting the safety of tourists and residents in the scenic spot,and ensuring the safe operation of the scenic spot.Based on the"Huguan Taihang Mountain Grand Canyon Tourism Resources and Geological Environment Evaluation Project",this paper complete a series of researches,to learn domestic geological disaster risk assessment methods,and to collect the results of previous geological disaster surveys in Qinglongxia Scenic Area.The refined survey results of geological hazards in Qinglongxia Scenic Area are the most important research data of this study,which is mainly obtained through 1:2000 geological hazard detailed survey,remote sensing interpretation and UAV 3D modeling,as well as other geological hazard survey methods.According to the survey results,the distribution law,development characteristics and influencing factors of geological disasters are summarized.Based on the raster overlay analysis function of Arc GIS software,the binary Logistic regression model and the analytic hierarchy process are used to evaluate the hazard and vulnerability of the geological disasters in the study area,and the results of the geological disaster risk assessment in Qinglongxia Scenic Area are obtained.Disaster prevention measures and suggestions are put forward for these areas with different disaster risk levels.The main results of this research are following:(1)There are 52 collapses and 17 landslides in Qinglongxia Scenic Area,with a total of 69geological hazards.The largest proportion of its scale is the small collapse.The main types are dominated by tensile collapse and toppling collapse,with small potential risk level.Geological hazards are densely developed on both sides of the Jiaogou River and Qinglongxia.During the period of human activities,the rainy season,and the spring freezing and thawing,the probability of geological disasters is high.Fault,topography,karst and stratum lithology affect the formation of geological disasters.Meanwhile,rainfall and human engineering activities have obvious effects inducing geological disasters.(2)The Rockfall Analyst software is used to simulate the falling rock movement trajectories of typical disaster points,such as tipping,tearing,and slipping,as well as high-level collapses.Furthermore,we analyze their movement characteristics and range of influence by an analogical method.Combined with the landslide disaster impact range surveyed on site,this paper draw a map of the area distribution of geological disasters in the study area.(3)Based on the disaster investigation results and the analysis of hazard-causing factors,7main evaluation factors are selected to establish the hazard evaluation system of Qinglongxia Scenic Area.The binary Logistic regression model is used to determine the factor weight coefficients,and the hazard grid is calculated through the grid overlay function in Arc GIS software.According to the calculation results,the Qinglongxia scenic spot is divided into four levels of hazard zones:extremely high,high,medium,and low.The area of extremely high class is 2.02km~2 with 31 geological disasters,including Hedong Village,Dahe Village,Yangjiachi Village,Qinglongxia Tourist Area,Dahe Drifting and Nuwa Cave Tourist Area.The area of high class is 2.79km~2,including the southwestern and northern parts of the study area along the river valley,and there are 24 geological hazards.The area of medium class is2.91km~2,consisting of several natural villages,such as Dalinbei,Yangjingzhai,and Lingdong Village,which have6 geological disasters.The area of low class is 2.44km~2,mainly distributed on both sides of the Qinglongxia tourist area,with 8 geological disasters and relatively high altitude.(4)On the basis of field investigation,data collection and considering the tourism attributes of the study area,this paper selects seven evaluation factors to establish vulnerability evaluation system,including local residents,tourists,roads and bridges,tourism facilities,residential buildings,cultural landscape and natural landscape.AHP is used to determine the weight coefficient of these factors.The Qinglongxia Scenic Area is divided into four vulnerable areas:high,high,medium and low.The area of extremely high class is 0.13km~2,including the narrow area of Qinglongxia Scenic Area and both sides along the river rafting line.The area of high class is 0.29km~2,including Dahe Village,Hedong Village,and Xiao Jiuzhai-Qinglong Waterfall-Lover Lake.The middle class covers an area of 0.66km~2,mainly including Qiannao Village,Lingdong Village,Hounao Village and both sides of Provincial Highway S327.The area of low class is of 9.06km~2.This area is characterized by steep slopes,few livable areas and few human activities.(5)The hazard grid and the vulnerability grid are superimposed and multiplied to obtain the geological disaster risk distribution map of Qinglongxia Scenic Area,which is divided into four risk areas of extremely high,high,medium and low levels.The area of extremely high class is 0.38km~2,accounting for 3.77%of the area of the scenic spot.It is distributed in a north-south strip pattern,mainly including Dahe Village,Qinglongxia Tourist Area,Dahe Drifting,etc.The area of high class is 0.72km~2,accounting for 7.14%of the area of the scenic spot.It is mainly distributed along both sides of the S327 Provincial Highway,and includes natural villages with relatively dense populations such as Yangjiachi Village,Hedong Village,Xinao Village,and Hounao Village.The area of medium class is 3.59km~2,accounting for 35.43%of the area of the scenic spot,and is mainly distributed within the range of 50m to 500m on both sides of the high-risk area.The area of low class is 5.45km~2,accounting for 53.66%of the scenic area.Manyareas are uninhabited areas with dense vegetation and large undulations.(6)The thesis puts forward targeted disaster prevention measures and suggestions for different geological disaster risk levels,which provide an important basis for disaster prevention and mitigation in Qinglongxia Scenic Area. |
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