Research On The Hazard Assessment Of Area Landslide

Landslide is one of the most dangerous geological disasters in China.It has been threatening the transportation?city construction?water resources and hydropower some other economic activities and life of people,because of its high speed of outbreak and movement.So in nowdays,it's necessary to do some research which is about how to evaluate the risk of landslide.The paper depends on the national science and technology fund project that warning and forecasting system of strong rainfall induced landslides and debris flow,taking Zhongxian of Chongqing as the research scope,analysis the influential factors of landslide,from the following six concepts:the development history of landslide ?landforms?rainfall?hydrology and human activities,choose 12 factors to establish the index-system.meanwhile combine Analgtic Hierarchy Process with Coefficient of variation method,get the optimum weight of factors by using the method of combination weight,using the functions of GIS like reclassify?buffer analysis?zonal statistics and so on to get the data of factors,taking multiple factor models as the evaluation models,based on the 28 villages of Zhongxian,do some researches on the hazard assessment of landslide.The main research contents and results are as following:(1)From the following concepts:the damage of landslide ? hazard evaluation of landslide ? the influence factors of landslide ? the composition of index-system and evaluation models to elaborate the index-system of landslide,meanwhile,choose 12 factors,such as,landslide density to establish the index-system,use the way that combine AHP and Coefficient of variation method to calculate the weight of factors.(2)According to the history data of 350 landslides,do some research about the landslides in Zhongxian,get the following result:The cause of landslides in Zhongxian is rainfall;The area of landslides in Zhongxian are under 105m~2;The sizes of landslides in Zhongxian are medium and small;The distribution of landslide in Zhongxian are concentrated,most of them lie to the southeast of Zhongxian,such as Zhongzhou ?Dongxi?Fuxing,and so on,12 villages in Zhongxian;The occurrence time of landslide in Zhongxian,most of them happened after the 20 th century;Refer to landslides ?development,most of them developed in the lithology of J3p;Refer to topographic slope?relief amplitude and front elevation,the high hazard areas are 0°~20° ?20m~40m and 200m~400m;Refer to the number of affected residents?the area of damaged building and property damage,for most of the landslides,the number of affected residents are less than 50 persons,the areas of damaged building are more than 3000m~2,the loss of property are more than 750000 yuan.(3)With the help of GIS software,get the data of factors,and then using the function of reclassify to reclass the data,meanwhile using the function of zonal statistics to divide the data into 28 villages equally,after that,combine the best weight of factors and evaluation models to get the comprehensive evaluation of every factor in every village.(4)Based on the comprehensive value,using two different methods to get the critical value,one is curve method,the other is thresholding method,according to the critical value,and then get the risk zoning of landslides,do some research on the hazard evaluation of landslides,the two different results are as following:1)The result of curve method: landslides can be divided into four type areas:high hazard?medium hazard?low hazard and very low hazard area.The high hazard area is 533km~2,and 24.37% of the total area,which is located 6 villages of Zhongxian;The medium hazard area is 223 km~2,and 10.20% of the total area,which is located 4 villages in total;The areas of low and very low hazard are 1357km~2?74km~2,and 62.05% ? 3.38% of the total area,which are located 17 villages and 1 village of Zhongxian respectively.2)The result of thresholding method: landslides can be divided into four type areas: medium to high hazard?medium to medium hazard?medium to low hazard and low hazard area.The areas of medium to high hazard and medium to medium hazard occupied 11.71% ? 14.72% of total area separately,which is located Yangdu ?Zhongzhou?Dongxi,and so on,7villages in total;The areas of medium to low hazard and low hazard occupied 19.66%?53.91% of total area separately,Which is located Shizi?Mozi?Shanguang,and so on,21 villages in total.