The Development Law, Prediction And Evaluation On Landslide In Bazhou Area

The study area is designated prone to geological disasters,located in the northeastern of sichuan, Dabashan mountain foothill, the west of Dazhou, in a low hilly region of zhongshan, red rock of sichuan province.The landslides in Bazhou is not only a threat to cultivated land, forests, roads and railways, but also is a serious threat to the life of the villagers.According to incomplete statistics, The economic of Bazhou damaged to property, caused by landslides every year,is to hundreds of millions. Therefore, the studying for the development regularity and formation mechanism of landslide, and forecasting to landslide risk evaluation,is good to the disaster prevention and mitigation of geological disasters, engineering safety and environmental protection has practical significance.Based on the detailed study of geological background conditions and landslides, analyzed the development characteristics and typical landslide characteristics, researched the development regularity and formation mechanism of landslide. Analyzed variable dimension fractal characteristics of spatial distribution and the single factor sensitivity evaluation factors of landslides of Bazhong.transformed semi-quantitative into the quantitative analytic hierarchy process, afinally,the comprehensive index method is adopted to research area with a prediction of the landslide risk evaluation. The following main research results:(1)The area of Bazhou is located in the eastern sichuan low hilly region,valleys more and deep,middle mountain gradually transited to low mountain and hilly terrain from north to south.Mainly exposed Jurassic is PengPai town group, lower cretaceous CangXi and BaiLong group. stratum,lithology is sand shale interbed. In the area of study, fault is not existed and four wide folds existed.(2) Analyzed characteristics of 72 landslidesthe, there are 25 earthiness landslides and 47 rocky landslide, 5 large-scale landslide, 14 medium-sized landslide, 53 small landslides. no 2 landslide of ZhiYong Wu, Chen Jiayuan landslide and YuJiaBian landslide as a typical sliding, development characteristics of the landslide are analyzed in detail.(3) Detailed statistical analysis was carried out on the spatial distribution of landslides, summaried the development regularities of landslide: the main tectonic erosion landform parts of landslide development low zhongshan landscape(single), Jurassic strata lithology of penglai town group mudstones interbedded sandstone and cretaceous sandstone with mudstone, bailong group slope structure for shelving consequent slope, slope is 10 ° to 30 °, the elevation of 510 m ~ 1110 m, rainfall is greater than 1300 mm. The deformation of the landslide to break the pattern in the studied area, it is concluded that the landslide deformation failure mode has 3 kinds: creep, cracking, slip, cracking, horizontal pushing type, and analyzed the formation mechanism of.(4) On the basis of landslide development regularities, selected the landscape area, stratigraphic lithology, slope structure, slope, elevation, rainfall, earthquake and human engineering activities as evaluation factors.sensitivity analysis is made for evaluation factors of landslide, and researched the variable dimension fractal characteristics of the spatial distribution of landslide, it is concluded that the fractal dimension value of the evaluation factors are: the slope body structure(1.482),(1.792) and slope height(1.082), formation lithology, rainfall(0.273)(0.863), landscape(0.219), human engineering activities(0.241), the earthquake(0.1).(5) Combined with fractal dimension values, the quantitative evaluation index weights using the analytic hierarchy process(ahp) is respectively: slope structure(0.237),(0.330) and slope height(0.165), formation lithology(0.121), precipitation(0.039)(0.050), landform, human engineering activities(0.039), the earthquake(0.019). Evaluation factors of quantitative indicators to make use of ARCGIS grid overlay, get comprehensive index F(0.061 ~ 0.992), according to the threshold limits the research is divided into: high danger zone and high danger zone, middle zone, low risk area. Prediction results in conformity with the field survey results, proving that the prediction evaluation is reasonable.