Analysis On The Characteristics Of Landslide Disaster In Lushui County And The Study On The Zonation

Lushui county is located in mountain and ravine region of west Yunnan with complicated conditions of natural geography、meteorological hydrology、geological structure and fragile ecological environment. It is one of the areas greatly suffered from geologic disasters especially landslide and collapse in Yunnan province.This research studied the development and distribution characteristics and geological hazard susceptibility of landslide and collapse. The development and distribution characteristics and space-time distribution pattern were analyzed based on data of natural geography、Meteorological hydrology、geological structure and human engineering activity in the study area. Then on this thesis, slope、aspect and so on 8 factors were choosed to be the main influence factors of landslide and collapse in the study area. The distribution situation of landslide and collapse in 8 main factors and the sensibility of each factor to landslide and collapse were analyzed by using function of spatial analysis of GIS. Finally, the susceptibility of landslide and collapse was assessed respectively based on the grid cells and slope units by using the improved hazard susceptibility model of AHP-information computation method. For verifying the accuracy of the model, contrastive analysis and reality Testing were carried out on the results of assessment. From what has been discussed above, we obtain the following main result and cognition:①、The natural geographical、meteorological hydrological and geological structure of Lushui county were analyzed systematically. High mountain steep ravines、broken rock mass affected by structure and concentration of rainfall and human engineering activities provides a good pregnant induced mechanism condition for landslide and collapse.②、Statistical analysis was performed on the development and distribution characteristics of landslide(235) and collapse(90). In the matter of development characteristics, this paper mainly summarize developing types、size and morphological characteristics. In the matter of distribution characteristics, analyzing space-time distribution pattern and concentrating on aggregation and trend.③、Elevation slope, aspect and so on 8 factors were chosed to be the main disaster-inducing factors based on the study of development and distribution characteristics of landslide and collapse and the real situation of investigation. The disastrous rule was summarized by statisticed the relationship between disasters and factors causing disaster using relative density method including number- relative density method and area-relative density method.④、The selection of mapping unit was discussed and the mapping unit comes down to 4 kinds:the regional units, grid unit, uniform conditions units, slope units. According to the needs, the evaluation of the geological hazard in this paper chose slope units and grid unit. Divide grid unit by using DEM. Divide slope units by using hydrological analysis method.⑤、Establish hazard susceptibility model of AHP- information computation method by improving insufficient of AHP method by using the advantages of objective and accurate of information computation method. Based on this model, the susceptibility of landslide and collapse was assessed within 8 factors:elevation、slope、aspect、mass of rock、average annual rainfall、the fault distance、the distance from population centers.⑥、The results of assessment shows that the slope unit assessment result is more accurate, economical and practical by comparative study of slope unit assessment and grid unit assessment. Based on that, the study area was divided into 5 "high"’areas,2 " moderate" areas and 3 "low" areas an. And then make a comment to each area.