Research On Characteristics And Risk Assessment Of Geological Hazards In Shanyang County

Shanyang County is located in the Qinba Mountains in southern Shaanxi.The topography and geomorphology of the area are quite different,and the geological environment conditions are complex.With the addition of human engineering activities,the geological and environmental problems are more prominent.Therefore,it is particularly important to carry out research on the risk assessment of geological disasters in Shanyang County.Based on the"Shanyang County Geological Hazard Risk Investigation and Evaluation"project,this research carried out the geological hazard risk evaluation and zoning research in the study area.The main results are as follows:(1)There are 465 hidden danger points of geological disasters in the study area,and there are mainly 4 types of disasters.Among them,445 landslides,occupying 95.7%of the total land;8 collapses,accounting for 1.72%of the total;10 hidden debris flows,accounting for 2.15%of the total;2 ground collapses.(2)Ten indicators including landform type,river,road,rainfall,slope height,engineering geological rock group,geological structure,aspect,slope type,and slope are selected as the hazard-pregnancy factors of the study area,and the statistics of each hazard-pregnancy factor at different levels According to the statistical results,the selected hazard-pregnancy factors are reasonably classified based on the number of distribution and disaster point density,and then the correlation analysis between the factors is carried out,and the geomorphological type factors are eliminated,and a risk evaluation index system is established for the remaining 9 hazard factors.(3)Based on the Arc GIS platform,the weight of evidence model is selected to carry out the risk evaluation research,and the evaluation results are verified by two methods.The results show that the test accuracy is high,indicating that the research results of the geological disaster risk evaluation based on the weight of evidence model are more reliable.(4)The vulnerability evaluation of disaster-bearing bodies in the study area selects population distribution,building distribution and road distribution as evaluation factors.The vulnerability assessment of the population is through Arc GIS for point density analysis;the vulnerability of buildings and roads is constructed through the construction of vulnerable buffers.The vulnerability of each factor is assigned a value,and finally the evaluation factors are superimposed to obtain the vulnerability evaluation result.The results show that the areas with higher vulnerability are the county and urban areas and the seat of the township government,which is consistent with the actual situation,and the vulnerability assessment results are more accurate.(5)According to the"risk is equal to the product of risk and vulnerability",the risk assessment results of geological disasters in the study area are obtained:the areas of extremely high,high,medium and low geological disasters are 272km~2,542km~2,1879km~2and 842km~2,respectively,accounting for 7.69%,15.33%,53.15%and 23.82%of the total area of the county.Based on the research results,the areas of different risk levels in each town were counted,and the risk assessment results were refined to each village group.(6)Based on the results of the regional risk assessment,suggestions on geological disaster risk management and control of"point control"plus"surface control"are put forward,and corresponding prevention and control measures are given.