| Landslide disaster has the characteristics of multi type,large-scale,frequent occurrence and wide distribution.It is a kind of geological disaster with great harm.The formation and development of landslide disaster poses a great threat to the life and property safety of local people.Gongxian County is located in the south of Sichuan Province,with complex geological environment,strong human engineering activities,high degree of development of geological disasters,and the largest proportion of landslide disasters,which has had a serious impact on the local area,so it is urgent to evaluate the susceptibility of landslide disasters.Combined with the"first national comprehensive risk survey of natural disasters in Sichuan Province"and the"comprehensive risk survey of geological disasters in Gongxian County,Yibin City",this paper analyzes the development characteristics,distribution rules and disaster pregnant conditions of landslide disasters in Gongxian County,Sichuan Province,based on the natural geography and geological environment of Gongxian County,and completes the construction of the evaluation index system of landslide disaster susceptibility in Gongxian County,Sichuan Province,The evaluation model of landslide disaster susceptibility in Gongxian County,Sichuan Province was established,and the highest accuracy evaluation model was selected through comparative test to realize the landslide disaster susceptibility evaluation in Gongxian County,Sichuan Province.The main achievements are as follows:(1)The development characteristics and disaster pregnant conditions of the landslide disasters in Gongxian County are analyzed in detail.The landslide disasters in Gongxian County are all soil landslides,and the material composition is loose earth rock,which are all loose accumulation landslides;There are 92 landslides induced by natural factors and 44 landslides induced by mixed factors;In addition to Yuhe Township,12 towns and townships in the county developed landslide disasters,of which Xiaoer town and Shangluo town developed the most,25 and 23 respectively;In the low mountain landform area,the slope is 16°-24°,the altitude is 500m-700m and the slope direction is southwest,the landslide disasters are most developed,which are 115,49,61 and 26 respectively;Landslide hazards are more developed in areas with small surface undulation and cutting,developed geological structures,weak properties of rock and soil mass and surface soil,along slope development,river development and strong human activities.(2)Based on the analysis of the development characteristics and disaster pregnant conditions of landslide hazards in Gongxian County,11 control factors such as landform,topographic relief,surface cutting degree,slope structure,slope gradient,engineering geological petrofabric,distance from fault,soil type,distance from river and human activities were selected as evaluation factors.All evaluation factors passed correlation analysis and collinearity diagnosis,The evaluation index system of landslide disaster susceptibility in Gongxian County,Sichuan Province was constructed by using 11 evaluation factors.(3)On the basis of constructing the evaluation index system of landslide disaster susceptibility,taking the grid unit as the evaluation unit,information model,certainty coefficient model,information logistic coupling model and certainty coefficient logistic coupling model were introduced to classify the landslide disaster susceptibility in Gongxian County,and the comparison and accuracy test were carried out.According to the comparison and accuracy test results of the four models,the AUC value of the certainty coefficient logistic coupling model was 0.804,The accuracy of the model is the highest among the four models.Using the zoning results of the model,the susceptibility assessment of landslide disasters in Gongxian County was completed.The results are as follows:the area of high susceptibility area is 228.37km~2,accounting for 57.35%of landslides;The moderate prone area covers 291.95 km~2,with landslide accounting for 25.00%;The low-risk area is 279.75km~2,with landslide accounting for 11.76%;The low-risk area covers 340.07 km~2,with landslide accounting for 5.89%. |
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