Study On Characteristics And Risk Assessment Of Strong Earthquake Landslide In Diexi Area

The monitoring and early warning of landslides is a worldwide problem.The study and solution of this problem not only require the efforts of engineering geology and geotechnical mechanics,but also the depth of integration with modern geophysics,mapping,geographic information and remote sensing and meteorology,as well as advanced theoretical and technical methods resulting from it.Support.At present,the methods used for landslide monitoring include precision leveling,satellite remote sensing technology,optical fiber sensor,close range photogrammetry,ground laser scanning,and so on.InSAR and LiDAR technology have also been applied to the early recognition of landslides,but these methods have various defects,such as small monitoring range,difficult measurement and view.Long period and high cost are measured.However,it is very important to quickly "find out" the hidden danger points of these landslides for the mountainous areas with very complex topographic and geological conditions,frequent earthquakes and many landslides.This paper,based on the project of "Gansu Tianshui City and Chenglan traffic corridor engineering geological survey",takes the zidai area as the research area to carry out the study on the characteristics and risk assessment of the landslide development in the strong earthquake area,aiming at establishing the risk assessment model of the landslide in strong earthquake area,providing a theoretical basis for the early recognition of the sliding slope after strong earthquakes.In this paper,through the collection of data and field investigation,the meteorological and hydrology,topography,lithology,geological structure,neotectonic movement and earthquake,engineering geological features and human engineering activities in the study area are thoroughly analyzed and elaborated.On this basis,the typical landslides in the study area(New Mill Village landslides)are discussed.The depth analysis of yangliucun landslide is carried out,and the characteristics of strong earthquake and landslide in the study area and its control factors are summed up.Then,based on the characteristics of the strong earthquake landslides in the study area,the evaluation index system of the landslide hazard is established,and the risk assessment is carried out by GIS technology.Finally,the slip distance prediction is carried out for the typical strong earthquake landslides in the high risk area.Research? The main conclusions are as follows:(1)The geological structure of the study area is complex.The new and old structures of different times and different tectonic systems are interwoven with each other,causing the old structures to be fragmented and the new structures are intermittent.The engineering geological conditions in the area are complex and easy to induce landslides.(2)There are 37 strong earthquake landslides in the study area,which have the characteristics of broken rock structure,earthquake crack,high position,high speed slide,non development slide zone between accumulation body and lower accumulation body,but the disturbance zone formed by huge impact(the composition of landslide accumulation and the underlying accumulation body is mixed up in one).(3)The controlling factors of strong earthquakes and landslides in the study area are stratigraphic lithology,geological structure,slope,relief and structural type of slope.The strong earthquake landslides in the area are densely developed along the range of 800 m near the fault zone;the slope has the largest density when the slope is 45 ~60 degrees,and the greater the potential energy of the slope,the more easily the landslides develop,and the landslide development density is large on the bedded slope,and the landslides on the reverse stratiform slope have small development density.(4)The high risk areas of the landslide in the study area are mainly distributed in the left bank of the pine Ping ditch,the left bank of the charcoal gully in the left bank of the fish village gully and the small Guanzi village.The dangerous areas are mainly distributed in the right bank of the fish village ditch and the high altitude unmanned area,and the low dangerous areas are distributed in the study area.The terrain fluctuation is small,the slope is slow and the landslides are less developed.The extremely low risk area is mainly distributed in the Pine Valley,the valley of the fish village and the open area of the Minjiang River.(5)According to the calculation formula for the slip distance of the slope surface and the internal friction angle of the new mill village landslide,the sliding distance of 3 typical high dangerous landslides is predicted,and the sliding distance of a landslide is 2556 m,and the 2 landslides can be able to block the river.