Regional Slide Hazard Assessment Based On Logistic Analysis And GIS In Jian Zha County Qing Hai Province

On the basis of investigation of geological disasters about landslide in in JianZha county QingHai province,this paper take some experiments on mechanics and mineralogy and analyze landslide formation mechanism and the inner development mechanism about typical landslide KangYang landslide and LaSa landslide.The authors found that the red mudstone control the development of landslide.Internal reason of landslide starts is that water in water channel of mudstone formation wet mudstone and mechanical property of mudstone declined rapidly after mudstone had been wetted.High proportion content of clay minerals particularly expansion properties of clay mineral in mudstone are the important reason for the special mechanical properties.The clay mineral content of sliding zone position of two landslide are higher than other parts.It is proved that content of clay mineral is inversely proportional with mechanical properties of rock and the strata with high content of clay mineral become a potential weakness.According to the information processed by ArcGIS software,the author preliminary selected eight factors of "elevation difference","grade","height" and "distance to Residents ","distance to road","distance to river","slope","strata" and generated spatial geography database.Then make regional landslide hazard assessment to JianZha county based on the statistical analysis of factor analysis and logistic regression method on GIS platform.Removing the correlation of influence factors by using the method of factor analysis.Then the original primary eight factors were translated into four principal component factors by the descending dimension algorithm.So "principal component space geographic data" be generated on GIS platform.Then taking logistic regression analysis for the 73 landslide samples and 200 not landslide samples With four principal components as independent variable on SPSS platform.So the landslide hazard zoning map is formed on ArcGIS according to results of logistic regression.The following conclusion was gotten according to the evaluation results.(1)The high risk area of landslide development mainly concentrated on the northeast,southeast and southwest depression of JianZha county.From northeast to southwest,the degree of danger was gradually reduce.It was consistent with the field investigation.(2)The distribution of high-risk groups is closely related to human activities and the specific formation on small scale and mainly distributed the location with frequent human activities and half cementation cretaceous and Neogene mudstone strata.The strata has the characteristics of the layer distribution between hard and soft rock,the permeable layer and the impermeable layer.(3)The rivers and degree of relief has important influence for landslide development.But the influence is not a patch on strata factors and human engineering factors.(4)In this paper,the logistic regression method improved by factor analysis is creatively used in regional disaster assessment.This method greatly improve the credibility and accuracy of the evaluation results then before.