| Mianning County is located in the southwest of Sichuan Province and northwest of Liangshan Prefecture.It is located in the northern section of the north-south tectonic belt of Sichuan and Yunnan.The geological structure is more developed,and many earthquakes,heavy rains and human engineering activities have occurred in history.Mianning under the jurisdiction of six towns,32 townships,232 villages,population 318585 people;traffic is very convenient,Jingkun high-speed Ya Pan section,108 National Road runs through the north and south,provincial road 215 crossed things;Hydropower development,mineral resources mining,repair building road and other human engineering activities frequently.The occurrence and evolution of landslide geological hazards threaten human engineering activities and property,and carry out risk assessment of landslide geological hazard in Mianning County to provide reference for human engineering activities such as disaster prevention and mitigation,construction and road location in landslide development and reduce coronal Ningxia landslide geological disasters caused by casualties and property losses,to promote economic development and social stability and harmony has a very important practical significance.Based on the survey and reconfiguration of the landslide geological hazards in Mianning County,137 landslide disasters developed in China are taken as the object of this paper,and the risk assessment and division of landslide geological hazard in Mianning County are carried out.The risk assessment of regional landslide geological hazards is mainly based on the evaluation of risk assessment and vulnerability.The overall framework of this paper is also based on this.Through the evaluation of the risk of landslide geological disasters in Mianning County,the main results are as follows:(1)Mianning County,a total of 137 landslides developed,of which the main low-grade landslide,accounting for 95% of the total number of landslides,Chengxiang Town,Town,Qingnai Township,Cao Township,four township landslides geological disasters are the most developed.From the analysis of the time and spatial distribution of landslide geological disasters in Mianning County,the landslide disaster is mainly distributed along the river and fault zone.It is concentrated in the metamorphic rocks such as slate,sandstone,phyllite and siltstone.And more developed in the slope of 10°-40° slope area;mainly along the highway along the strong development of human engineering activities in the rainy season and rainy days relatively frequent.(2)On the basis of this,the author makes a statistical analysis of the predisposing factors and the predisposing factors of the landslide geological disasters in Mianning County,and classifies them according to the different degree of contribution of the landslide hazard in different classification intervals.PoA,PoLN,The relationship between the influence factors and the distribution of landslide geological hazards is analyzed statistically.The results show that the geological disasters in Mianning County are between 10° and 20° slope,and the slope is northwest and south east.The slope height is between 20 m and 40 m,and the Permian and Triassic strata are concentrated.The more developed the landslide disaster is,the more the annual rainfall and the peak of the earthquake are accelerated.The more the landslide is the relative development.(3)Based on the analysis of the spatial and temporal distribution of landslide geological hazards in Mianning County and the analysis of the prone factors and induced factors of landslide geological disasters,the slope,slope,slope,stratigraphic lithology,geological structure,river system,earthquake,Rainfall 8 leading factors as the Mianning County landslide geological hazard risk assessment indicators,the use of ArcGIS software spatial overlay analysis function Mianning landslide geological hazard risk zoning.In this paper,the risk assessment was carried out by using the analytic hierarchy process(AHP),and the ROC curve was established by the information method.The correctness of the evaluation results was evaluated by the percentage of the area under the AUC.The evaluation results of the two methods were highly consistent The accuracy of the risk assessment results was 78.53%.(4)This paper chooses three indicators of population density,highway and land resource utilization as indicators of vulnerability assessment of landslide geological hazard in Mianning County,which divides the total population of townships into the corresponding housing area as the spatial expression of population density,The value of the road's line density is quantified by 2 km for the search radius,and the land resource vulnerability is quantified by the price per unit area of the land resource.In order to eliminate the influence of different dimensions between the evaluation indexes,Do the normalization.The weights between the evaluation indexes were calculated by using the analytic hierarchy process.The weighted sum model of ArcGIS software was used to evaluate the vulnerability of the landslide in Mianning County.(5)In this paper,the risk assessment of the geological disaster of Mianning landslide is carried out by quantitative method.The risk index normalized value(H)and the vulnerability index normalization value(V)are used to calculate the risk of landslide geological hazard by R=H×V empirical formula Index and re-classification to get the risk stratification of the landslide geological hazard in Mianning County,and use the spatial overlay function of Arc GIS software to superimpose the risk zoning result layer and the administrative unit layer of Mianning County,and finally get the risk stratification result. |
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