Risk Assessment Of Debris Flow In Northern Mountainous Areas Of Dalian

Debris flow is a geological hazard phenomenon.It not only destroys the ecological environment,but also seriously threatens the lives of the people.The risk assessment of debris flow is based on the investigation and study of such environmental factors as landform,geological structure,meteorology and hydrology,vegetation and human activities in a specific area,which are easily leading to debris flow.According to certain methods and standards,the dangerous degree of debris flow in this area is analyzed,and the hazard range is predicted and the process of hazard regionalization is carried out.In view of the large population and dense assets in the northern part of Dalian,and the geological disaster of debris flow has the characteristics of sudden occurrence,the damage in the affected area is heavy.In order to better serve the disaster prevention,mitigation and relief work of debris flow geological disaster,and reduce its influence,this paper studies the risk evaluation of debris flow in the northern mountain area of Dalian.On the basis of a large amount of literature and on-the-spot investigation,this paper takes Laomaoshan area as the experimental area,and evaluates the study area with fuzzy comprehensive evaluation method and Liu Xilin debris flow risk degree "four-value and five-grade" judgment method.According to the on-the-spot comparison,the results are consistent with the actual situation,and it is proved that this method is applicable to the risk assessment of debris flow geological hazards in Dalian area.The method is applied to the evaluation of three northern areas of Dalian City,namely,Wafangdian City.Pulandian District,Zhuanghe City,including 10002 square kilometers,and obtained the results of the study.The study includes the following processes:(1)divided into evaluation units.Gis was used to divide the study area into 9329 evaluation units.(2)the index system was constructed.Considering the basic conditions of debris flow,eight evaluation indexes such as height,height difference,slope,vegetation,annual average precipitation,soil erosion intensity,land use type and soil texture are selected.(3)data collection and data extraction.Including 30 m resolution DEM data,vegetation index,soil texture,soil erosion intensity,land use type,annual average precipitation,etc.,and use gis to extract the value of each evaluation unit.(4)to determine the index weight.The method of determining the weight of Indexes Using analytic hierarchy process.(5)risk assessment.The fuzzy comprehensive evaluation model and the "four-value and five-level" logic method of Liu Xilin's debris flow risk evaluation are used to evaluate the debris flow risk in the study area,and the results of debris flow risk distribution are obtained.The results show that the risk of debris flow is higher in Buyun Mountain Township,Rong Hua Shan Town,Changling Town,Lotus Mountain Town,Tongyi Township,Ambo Town,Siping Town,Le Jia Manzu Township and Wafangdian City in Zhuanghe City.