Research On Risk Assessment Of Geological Disasters Along The Highway Of YangMingHu Scenic Area

Yangming Lake Scenic Area is located in the southwest border area of Ganzhou City,Jiangxi Province,and the scenic road runs through Shangyu and Chongyi counties,and the research scope is mainly along the scenic road.Due to the influence of human engineering activities and other inducing factors,geological disasters such as landslides and collapses along the highway occur from time to time,inducing unstable slopes,resulting in many hidden danger points along the highway.This not only has a bad impact on the geological environment,but also seriously threatens the life and property safety of local residents and tourists,and restricts the long-term economic development of the two counties,making the contradiction between the geological environment and sustainable economic development increasingly prominent.Therefore,the risk assessment and research of geological disasters along scenic highways is of great practical significance to maintain the safety of local residents and tourists,and promote the sustainable development of the economy and tourism of the two counties.Based on the Science and Technology Research Project of Jiangxi Provincial Department of Education,"Prediction of Landslide Risk Considering the Hydrological Effects of Vegetation Communities in High Forest Coverage Areas",this study carried out risk assessment research on geological disasters along scenic roads.Firstly,taking the Yangminghu scenic highway as the research object,the number,development type,characteristics,scale,time and spatial distribution of geological disasters along the highway were obtained through remote sensing interpretation and field field investigation.Combined with the topography and geomorphology,geological structure and other conditions,a risk assessment index system was constructed to carry out risk assessment;The geological disaster environment in the study area was analyzed,and the vulnerability index was established and the vulnerability evaluation was carried out.Based on the risk and vulnerability evaluation results,a risk assessment index system suitable for the characteristics of geological disasters in this region was constructed,and the evaluation model was established,which enriched the theoretical system of scenic highway risk assessment to a certain extent,and the evaluation results also provided a theoretical basis for the local geological disaster prevention and control department to formulate disaster prevention and mitigation measures,which has certain practical value.The main conclusions of this study are as follows:(1)Based on the topography and geological conditions of the research area,the correlation between the engineering geological conditions along the highway and geological disasters was analyzed.At the same time,field investigation and remote sensing image interpretation showed that the unstable slope was mainly distributed on both sides of the highway due to engineering activities and rainfall factors,and the scale was large.Landslides and collapses are mainly small-scale,and on the whole,geological disasters are mainly linearly distributed along the highway,in the bank slope valley area near the water area on both sides of the road,and the fault structure development area.(2)Through the analysis of the development characteristics and distribution law of geological disasters,the Pearson correlation coefficient method and the multicollinear diagnosis method were used to eliminate the indicators with high correlation and strong collinearity,and finally 12 factors such as DEM,slope,aspect,section curvature,plane curvature,stratum lithology,distance from fault,distance from water system,TWI,NDVI,distance to road,and land use type were selected as risk evaluation factors to construct a risk evaluation index system.Based on the analytic hierarchy method(AHP),random forest(RF)model,frequency ratio(FR)and BP neural network,the coupled AHP-RF,FR-IOE and miv-BP coupling models were constructed as risk evaluation models,and seven methods were used to evaluate the hazards.Through the evaluation results,it can be found that most of the geological hazard points are located in higher and high risk areas.After the ROC curve verification,it is found that the coupling model of analytic hierarchy method integrated into the random forest model has the largest AUC value,and the prediction rate is 87.3%.Followed by AHP,RF and fr-IOE evaluation methods,AUC values were 87.2%,86.5% and 82.5%,respectively.The results of the four evaluations were higher than 80%,indicating that they were all suitable for the risk assessment in this area,and the evaluation accuracy was higher than that of the AHP-RF model.(3)Four indicators such as population distribution,scale,vehicle detour ability,and the degree of impact of highways on scenic spots were selected to construct a vulnerability evaluation index system,and the rating and weight calculation of different grades of each index were calculated by the scoring principle of analytic hierarchy,and four vulnerable layers were obtained after assignment.The Fuzzy Analytic Hierarchy Method(FAHP)was used to calculate the comprehensive weights of each index,and the vulnerability evaluation area map of the study area was obtained after superimposed processing.According to statistics,the areas along the highway are mainly low vulnerable areas and high vulnerable areas,and the area of vulnerable areas accounts for 29.04% and 36.91% respectively.On the whole,the higher and higher vulnerable areas are mainly distributed along the core scenic spot S547 highway,so the vulnerability of the highway is high.(4)The four coupling models of risk assessment(AHP,RF,AHP-RF,FR-IOE)were superimposed with the analytic hierarchy method(AHP)of vulnerability assessment to obtain the distribution map of geological disaster risk assessment along the highway.After field verification and risk level zoning comparison statistics,it is found that the risk zone after the superposition of the risk assessment coupling model(AHP-RF)and the vulnerability evaluation model(AHP)is more in line with the actual situation,that is,the distribution range of medium,high and high-risk areas along the S547 highway in the core scenic spot of Yangming Lake is large.Among them,the area of higher and high-risk areas accounted for 21.03% and 3.78%respectively;The area along X387 highway is mainly lower and medium risk areas,and the area of medium risk areas accounts for 20.81% of the total area;The G357 highway is dominated by low-risk areas.On the whole,the risk level along the S547 highway in the study area was the highest,and the medium-risk area,higher and high-risk areas were all distributed in the highway,which was more risky.