| The study area is located in the southeast of Tibet,north of the eastern of Himalayas,the middle of the Yarlung Zangbo River.With intense neotectonic activities,complex geological structures,there are large number of large-giant geologic hazards distributed in this area under complex geological conditions.Based on field investigation and remote sensing,geologic hazards spatial database were established along the Jiacha County to Lang County along the Sichuan-Tibet railway.Based on the interpretation of Landslide Remote Sensing and the field survey of landslides,the landslide spatial database of the Sichuan Tibet railway was established.The ground elevation,the terrain slope,the ground slope,the plane curvature,the lithology,the distance from the river,the distance from the fault zone,the distance from the channel Road and the NDVI(normalized vegetation index)aswell as the annual average rainfall were selected.Based on the ArcGIS software platform,we use the weight of evidence model and the frequency ratio ratio model to evaluate the landslide susceptibility in the study area.The main conclusions are as follows:1?The geological conditions in the study area are complex,so geological disasters are relatively developed.The main types of geological disasters are landslide,collapse and debris flow.The landslide is dominated by medium scale,the debris flow is dominated by medium and small scale,and the collapse is dominated by small scale.The geological hazards in the region have obvious spatial distribution regularities,time distribution regularities and lithologic distribution regularities.2?The landslide susceptibility evaluation system in the study area is established by using WOE model and FR model.By calculating the weight values of each shadow,we can see that the main factors that affect the development of landslide are fracture zone,lithology,roads and rivers.Through the factor classification chart and the spatial distribution of the landslides,it can be seen that the landslides are mainly distributed in areas with low altitude,slow slope,low surface vegetation coverage and low rock hardness,which are mainly along the road,river and fracture belt.In general,the closer the distance to roads,rivers and fault zones is,the larger the development area of landslide will be.3?According to the analysis results of landslide susceptibility assessment,the study area is divided into 4 levels according to the vulnerability of landslides,which are extremely high prone area,high prone area,medium prone area and low prone area.The susceptibility of landslides in the study area is characterized by high susceptibility to landslides in the south-west region and low susceptibility to landslides in the northeast area.The number of landslides developed in the high and frequent areas is more than 86% of the total number of landslides.The results are in good agreement with the known distribution of landslides.The results of the study are in good agreement with the distribution of the known landslides,which can provide a reference for the planning and construction of the large-scale human engineering activities such as the Sichuan Tibet Railway.4?The success rate curve was used to test the results of vulnerability assessment.The correct rate of WOE model reached 0.83,the accuracy of the FR model reached 0.80,and the two models had good accuracy. |
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