Reservoir Bank Geological Disaster Susceptibility Assessment And Study On Zoning Of Disaster Risk In Benzilan Water-source Reservoir Area Based On3S Technology

In recently years, the geological disasters occurred frequently due to globalenvironmental deterioration. The study of geological disasters susceptibility, hazard,vulnerability or harmful and risk is the focal point and difficulty in the disasterprevention and mitigation process, and attracts many researcher’s concern andattention. China is a country characterized by vast territory, extensive mountainranges, special geological structure and topography features, which can provide agood geological environment for breeding geological disasters. Therefore, China,specifically the southwest that locates a transition zone between the first step and thesecond step, is one of countries seriously affected by geological disasters in theworld. Landslide is a kind of common geological disaster occurred in China.Landslide characterized by widely distributing and frequently occurring bringsserious threat to people lives and property. As we all know, landslide disasters thatlocated in large scale hydropower project reservoir area once occurred will seriouslythe dam site safety, reservoir function properly, and people’s lives and property.Therefore, susceptibility and risk assessment research not only have great academicsignificance value, but also can provide scientific data for local government to makedisaster prevention and mitigation measures, having great practical value.In this paper, the3S technology was introduced into landslide study. Based onthe3S technology, laboratory analysis and geological survey in the field, we analyzed the bank stability, spatial distribution and early stability of landslides.Three dimensional digital model of landslide was established based on the SPOT5remote sensing imag. Under the help of rock type and rock attitude data, obtainedfrom field geological survey in the special geological point, a method is proposed toanalyze landslide formation mechanism in the areas where there are less drillingdata.Landslide characteristics, river bank structure, lithology, topography, geologicalstructure, and predisposing factors are taken into consided to analyze the majorfactors that effect bank landslide susceptibility. At last, fifteen major factors wereselected to establish evaluation index system. Combination weighting theory wasused to assign each evaluation index with a rationl weight. And then, bank landslidesusceptibility assessment model was established based on the unascertained measureand credible degree recognition criteria theory. In this study, four bank landslidesusceptibility classes were constructed: very light, light, moderate, and very high.And the reservoir area bank was mapped with different landslide susceptibility level.According to the assessment results, ten bank segments were classified as havingvery light susceptibility prone to landslide, thirteen segments as light, sixteensegments as moderate, and two moderate as high susceptibility prone to landslide,respectively. And, three, thirteen and eight landslides distribute in light, moderateand high susceptibility bank segments, respectively.In this paper, nine major factors that related with lithology, topography, faults,rver system and predisposing factors are selected to evaluate landslide hazard andmake hazard map. Based on the ArcGIS platform, the major factors and evidencelayers are extracted. And then, the fuzzy weights of evidence model and thecomprehensive hazrd index model are respectively utilized to evaluate landslidehazard and make landslide hazard map. The result shows that the very high and highhazard areas mainly distribute in Jinsha and Dingqu river both sides. The populationdensity, building density, road density, residents’ per capita annual income and arableland density are extracted as landslide vulnerability assessment index. Village isdetermined as the basic evaluation unit. Integrated vulnerability index model is utilized to evaluate landslide vulnerability. The final result shows that the very highand high vulnerability area accounting for7.62%of the total area, and mainlydistribute in the village with high degree of people activity. On the basis of landslidehazard and vulnerability assessment, landslide risk analyzing and risk map is made.The result shows that, the very high and high risk area accounting for19.70%of thetotal area, and mainly distribute in the areas with relatively developed economy andrelative concentration of population. Moderate and low risk area accounting for80.30%of the total area, and mainly distribute in those areas with relatively sparsepopulation, relatively few economic activity and relatively low building density.