Study On Regional Hazard Assessment Of Landslide Based On GIS And Monitoring Data

Zigui county is located on both sides of the Xiling Gorge and at the head of the Three Gorges Project.Landslide disasters occur frequently.At the same time,the development of regional economy highly depends on the regional population,agriculture,shipping and transportation resources.The contradiction between people's yearning for a better life and the uncertain and irregular periodicity of geological disasters has brought great challenges to disaster prevention and reduction.Economic and social development should always be based on a stable and safe land,so it is necessary to carry out risk assessment for the region,According to the regional risk level,the project layout should be carried out according to local conditions to provide theoretical basis and technical support for economic development and social activities to protect people's lives and property.This paper takes the first watershed of the Yangtze River and its main tributaries in Zigui section of the Three Gorges Reservoir Area as the boundary,combined with the experience of field inspection,this paper expounds the main types of landslides in the study area and the main structural types of the bank slope,summarizes the deformation development characteristics and evolution laws of landslides in the study area,and lists the influencing factors and deformation characteristics of typical landslides.With the help of Arc GIS software,the landslide hazard zonation map based on information weight and the landslide monitoring data extracted from professional monitoring points are generated by AHP and information model.The final landslide hazard zonation map is obtained by superposing the two values,and the single factor map is obtained by evaluation index The results are as follows:(1)Based on the Arc GIS platform,the location and type of the basic geological data of landslide disaster are input.Combined with the limited field inspection experience,the distribution and development characteristics of landslide disaster in the study area are summarized:the landslide disaster in the study area is mainly distributed in the west of Quyuan Town,along the water system,in the spatial distribution is uneven along the water system,traffic trunk line and gathering area Most of the landslides are distributed in the middle and low mountain landforms below the elevation of 600m.The landslides have a wide range of development,many types and great harm,and the number is mainly large and medium-sized.Their development is closely related to the lithology,and the geological structure is the basic condition for their development,while rainfall and water storage are the external conditions.At the same time,the landslide disasters and other geological disasters have vertical zonation,and most of the landslides are caused by unreasonable engineering Activities.(2)Through the further qualitative analysis of the relationship between landslide influencing factors and landslide disasters based on the regional physical and geographical conditions,regional geological conditions,human engineering activities and social development,and based on the principle of evaluation index selection,combined with the previous experience,the analysis shows that the slope,aspect,elevation,stratum,fault,bank slope structure,wading degree,rainfall intensity,highway stability,etc Distribution,surface coverage and other 10 factors can be used as risk assessment indicators.(3)The comprehensive landslide hazard zoning map based on information weight and monitoring data shows that the extremely high risk area is 93.57 km~2,accounting for 20.66%,mainly distributed on both sides of the Yangtze River in Quyuan town and along the main and tributaries of the Yangtze River to the west of Guojiaba town;The high risk area is 69.13km~2,accounting for 15.26%,mainly distributed in the periphery of the high risk area and along the main and tributaries of the Yangtze River to the east of Quyuan town;The medium risk area is158.93km~2,accounting for 35.10%,mainly distributed in the periphery of high risk area and a large number of high altitude areas to the west of Guojiaba town;The low risk area is131.21km~2,accounting for 28.98%.It is mainly distributed in the high altitude area to the east of Guojiaba town and other areas.(4)Through the single factor thematic layer obtained from the evaluation index,it is found that for the regional landslide analysis,the slope,aspect,elevation,wading degree,highway distribution,surface coverage and other evaluation indexes have a higher contribution rate to the risk assessment,while the stratum,fault and other evaluation indexes have a medium contribution rate to the risk assessment,while the bank slope has a higher contribution rate The structure,rainfall intensity and other evaluation indexes only have a low contribution rate to the risk assessment.