| There are many kinds of geological disasters in China,among which landslides are widely distributed and occurred frequently.Creeping landslide is a kind of landslide with small soil sliding,which develop slowly and have a long period of change.It can only be observed by instruments,and may develop into high-speed landslides in an instant,resulting in huge loss of life and property.Therefore,the monitoring of small deformation of landslide should be strengthened.The traditional monitoring methods consume a lot of manpower and material resources,low efficiency,and difficult to monitor the mountainous areas with complex terrain,which makes the analysis data inaccurate.InSAR can not only obtain large-range deformation information of the earth's surface all day,all-weather and free from the interference of clouds,but also image large-scale areas with millimeter-level accuracy.On the basis of InSAR,SBAS-InSAR can overcome the effects of spatial and temporal decoherence and atmospheric delay,and further improve the accuracy of processing results.The study area is located at the junction of Kangding-Danba-Xiaojin County,Sichuan Province,with developed water systems,convenient transportation and rich mineral resources.This paper mainly uses the principle and process of SBAS-InSAR to monitor the study area,providing data for sensitivity analysis and three-dimensional deformation analysis.The main research contents and work are as follows:(1)By using SBAS-InSAR to process and analyze the 9 ALOS PALSAR ascending images covering the study area,it is concluded that the average change rate of the study area is-322~175mm/year from November 17,2017 to February 22,2019,and the areas with large deformation mainly distribute around Dadu River.(2)According to the geological map of Sichuan Province,the distribution of formation lithology in the study area is obtained.Based on the SRTM1 DEM with an accuracy of 30 m,the slope,slope aspect,slope shape,elevation and river distance of the study area are extracted.Combining with the average deformation rate obtained by SBAS-InSAR,the influencing factors of landslide sensitivity analysis are composed.(3)The analysis method based on fuzzy theory is used to analyze the sensitivity of landslides.According to the analysis process of the method,the comprehensive values of various influencing factors are calculated,and the degree of difficulty of landslides is divided into five sections: extremely difficult area,relatively difficult area,intermediate area,relatively easy area and extremely easy area.The analysis method realizes the purpose of using different indexes of influencing factors to directly participate in the analysis of landslide sensitivity,and makes the results more objective and accurate.It can be seen from the weight of various influencing factors that the slope has the greatest impact on landslides,followed by formation lithology,average rate,elevation,river distance,slope direction,and slope shape,and the degree of influence decreases gradually.The analysis method is verified by using the typical landslide in the study area-Houziyan Kaiding landslide and Jiaju village regional slope,and it is concluded that Houziyan Kaiding landslide is in extremely easy area and Jiaju village regional slope is in relatively easy area.(4)In this paper,a preliminary study of the deformation characteristics of the landslide in three dimensions.Because the ground surface of landslide is not entirely horizontal in actual engineering,the concept of local incidence angle is proposed,and the formula of total displacement of the landslide is derived based on the spatial relationship with slope and aspect.By using the satellite data of ALOS-2 ascending or Sentinel-1 descending,the calculated total landslide displacement is compared with the original landslide displacement value obtained by SBAS-InSAR,comparing the calculated displacement values of two groups of data in the same area,and it is found that the model is reasonable for the calculation of landslide deformation.On this basis,the three-dimensional dynamic change of Houziyan Kaiding landslide is further explored.Through SBAS-InSAR and appearance monitoring,the change values of each component and the overall displacement in the threedimensional space are obtained,which are in good accordance with the actual change characteristics of the landslide,and the results of the two methods are in good consistency. |
PDF Full Text Request