Vulnerability And Risk Assessment Of Collapse And Landslide Disasters In Zizhou County,Shaanxi Province

Zizhou County,Shaanxi Province is located in the north of the Loess Plateau,with ravines and ravines,obvious differences in terrain,poor vegetation coverage,local residents have long been accustomed to building kilns according to the slope,wherever inhabited,the original slope has been transformed,so that the already relatively fragile geological environment has been artificially altered,resulting in a large number of potential hidden dangers of collapse and landslide.In recent years,with the increase in rainfall in northern Shaanxi,these potential hidden dangers can easily be triggered during the rainy season,causing disasters.Therefore,through the identification and on-site assessment of the potential dangers of collapse and landslides in Zizhou County,this paper systematically summarizes the distribution,characteristics,influencing factors and occurrence laws of collapse and landslides in Zizhou County,and selects seven indicators of slope,slope height,aspect,slope type,vegetation coverage,human engineering activities and rainfall as the evaluation factors of collapse and landslide hidden dangers,and establishes an evaluation index system for the susceptibility of collapse and landslide hidden dangers in Zizhou County.The analytic hierarchy method is used to determine the weight of the index,and after normalizing and quantifying the index,the information superposition method is used to carry out quantitative evaluation,and the comprehensive evaluation division is carried out according to the obtained results,which is divided into five levels:very high risk,high risk,medium risk,low risk and no risk.Among them,the area of very high prone area was 289.45 km~2,and the area of high prone area was 556.34 km~2.The area of medium prone area was 547.48 km2;The area of the low prone area was 392.71 km~2;The area of the non-prone area is 190.10 km~2.On the basis of the seven index factors of susceptibility evaluation,two index factors of hidden danger point density and building density were superimposed.After quantitative evaluation,the risk evaluation of collapse and landslide in Zizhou County was obtained,and after comprehensive evaluation of the zone,it was divided into four hazard levels:very high risk area,high risk area,medium danger area and low danger area.Among them,the area of the extremely high danger zone is 125.94 km~2;The area of the high hazard zone is 391.53 km~2;The area of the medium danger zone is 623.38 km~2;The area of the low hazard area is 836.81 km~2;Then,the area and scope of extremely high risk area,high risk area,medium risk area and low danger area are dynamically delineated according to the rainfall level,and the area of the extremely high danger area increases with the increase of rainfall level.It can be seen that the distribution of actual collapse and landslide hidden danger points in the study area is compared with the evaluation results,and the selected evaluation index system and evaluation method are reasonable and more in line with the actual situation.