Multi-classification Method Of Landslide Risk Assessment In Consideration Of Disaster Levels

In recent years,the frequent occurrence of multiple geological disasters has destroyed natural resources and the ecological environment,and has also caused serious losses to human property and social economy,leading to higher and higher potential risks faced by humans and society.Frequent geological disasters have gradually aroused people's attention and attention to various disaster prevention and mitigation measures.Preventing all kinds of disasters and reducing disaster losses have become major issues facing the world today.The geological disaster risk assessment is the prediction of the loss caused by the disaster.The geological disaster risk assessment is the prediction of the loss caused by the disaster.It can quantitatively assess the degree of risk caused by the disaster,and present it visually,providing a scientific reference for engineering construction,urban planning,and disaster prevention and mitigation.At present,most classification models of landslide hazard risk assessment are two-category,and less consideration is given to the impact of landslide hazard scale grade in disaster risk assessment,and there is a lack of multi-classification research on landslide hazard scale.When using the two-classification model for multiple classification,there are problems such as slow classification speed,large difference in the number of positive and negative samples,and large error in classification results.Therefore,this paper takes the landslide disaster in Xianyang City as the research object,and carries out a research on the risk assessment of the landslide disaster in Xianyang City by constructing a multi-classification landslide hazard model and a combined weight-based vulnerability evaluation model of the hazard-bearing body.The main contents are as follows:(1)Divide the hazard scale and risk level of geological disasters in Xianyang City.According to the scale of the disaster,the scope of impact,and the loss or potential threat,the geological disasters in Xianyang City are classified into low-hazard,medium-hazard,high-hazard,and extremely high-hazard,and the risk level is divided into no-risk,low-risk,medium-risk,highrisk,and high-risk five levels.Among them,the scale of geological disasters in the city is mainly low-hazard,with a total of 484,accounting for 75.981% of the total number of disaster points;disasters are mainly low-risk and non-hazardous,with a total of 350,accounting for 54.945% of the total number of disaster points.(2)Construct a multi-class SVM landslide hazard assessment model.Multi-type samples are selected according to the scale of the divided multi-level landslide hazards.Based on the landslide hazard factors,the multi-class SVM model is used to predict the hazard of landslide hazards in Xianyang City,and the multi-class SVM landslide hazard is constructed.Finally,the landslide disaster hazard in Xianyang City is divided into different regions to provide a basis for further landslide disaster risk assessment in Xianyang City.(3)Constructing a Vulnerability Evaluation Model of Landslide Hazards Based on Combined Weights.This paper uses AHP to determine subjective weights,entropy method to determine objective weights,combines the advantages and disadvantages of subjective and objective weights,uses the combined weight method to determine the comprehensive weight value of each evaluation factor,combines the vulnerability evaluation factors of Xianyang City,and uses the comprehensive vulnerability index model Calculate the vulnerability of objects in Xianyang City quantitatively,and complete the vulnerability evaluation study of geological disasters in Xianyang City.(4)Carried out the landslide disaster risk assessment research and analysis of the assessment results in Xianyang City.Combining the hazard evaluation of the multi-class SVM model and the vulnerability evaluation of the combined weight method,the landslide disaster risk evaluation in Xianyang City is completed.The village and town are used as the evaluation unit to analyze and summarize the risk size,and propose for disaster prevention and mitigation work suggest.Finally,according to the summary of the risk level and distribution of the existing landslide hazards in Xianyang City,the results of the landslide disaster risk assessment in Xianyang City are analyzed.