Research On Highway Slope Deformation Monitoring In Red Bed Area Of Central Yunnan Based On InSAR And TLS Technolog

Since the "14th Five-Year Plan",the highway construction in Yunnan Province has been moving towards the direction of high-quality development.However,there are many mountainous areas in Yunnan and the topographic geological conditions are complex.Especially in the middle of Yunnan,the relatively fragile red bed geology is widely distributed,which makes the slope along the highway prone to various geological disasters.Therefore,it is very necessary to monitor and study the deformation of highway slopes in the red bed area of central Yunnan.At present,there are many technologies and means used in the deformation monitoring of highway slope,but it is generally difficult to conduct comprehensive monitoring with a single technology for the fine deformation monitoring of large areas of highways.In this paper,the highway slope of some sections of Yongjin Expressway passing through the red bed area of central Yunnan is taken as the research object,and the monitoring of highway slope deformation combined with InSAR and TLS technology is carried out.The main research contents and conclusions are as follows:(1)Study on the monitoring technology scheme of InSAR and TLS.According to the regional characteristics of the highway research area,combined with the advantages of InSAR and TLS technology,a joint monitoring scheme of InSAR and TLS technology was determined.Firstly,the surface deformation of the whole large area along the highway was identified and monitored based on the time-series InSAR technology,and the hwidden danger of slope was identified and the target slope was determined.Then,TLS technology was further used to monitor the time sequence of the target slope,and more refined time sequence deformation results were obtained.(2)Identification and monitoring of highway surface deformation in large area based on SBAS-InSAR technology.Based on the SBAS-InSAR technique,the LOS deformation results of the ascending and descending orbits in the highway study area were obtained.The average annual deformation rates of the ascending and descending orbits were distributed in the range of-44～33mm/a and-52～38.5mm/a,respectively.The LOS deformation results of the ascending and descending orbits had certain differences in spatial distribution and specific values,because of the different sight directions of the ascending and descending orbits radar and the fluctuation of the ground.Therefore,the combined ascending and descending orbits can improve the reliability of identification to a certain extent.Two hidden slopes with large deformation along the highway were identified by combining the deformation results of ascending and descending orbits,and the identification results were verified by combining high resolution remote sensing image and DEM.The vertical and east-west deformations of the target slope were obtained by using the ascending and descending orbits InSAR two-dimensional deformation modeling.The vertical deformation rate was basically between-20～0mm/a,and the east-west deformation rate was between-15～10mm/a.The target slope was stable as a whole.(3)TLS refinement deformation monitoring for highway slope individuals.The technical scheme of TLS slope point cloud data acquisition was determined according to InSAR monitoring and identification results and field conditions.The point Cloud difference comparison method was explored.Based on Cloud Compare point cloud processing platform,the point cloud difference comparison method of registration,KD-tree nearest point search,local modeling and point to model distance calculation were determined to obtain the three-dimensional deformation of slope.Most of the deformations of the target slope in the three directions were small and the whole slope was stable.There were large deformation in the lower left and right corners of the slope,which was due to the incomplete slope support and soil accumulation in the two places during the first phase data collection.In the three-dimensional deformation direction,the vertical deformation in the Z axis was the most obvious,and the cumulative shape variables was distributed between-15 mm and 10 mm.(4)Comparison and validation of InSAR and TLS monitoring results and analysis of deformation factors.The same names of point cloud deformation results and InSAR two-dimensional deformation modeling results were determined by the coordinate of point cloud characteristic points,and their vertical deformation was compared and verified.The average annual deformation rate of the InSAR two-dimensional deformation model and TLS deformation results in the vertical direction was approximately the same order of magnitude,with the maximum difference of 14.29mm/a,the minimum difference of-0.35mm/a,and the average difference of 5.28mm/a.The deformation trend reflected by the two monitoring results was basically consistent.Then combined with the natural conditions of the study area and the monitoring results of highway slope deformation,the main factors leading to slope deformation were analyzed from the two aspects of internal influencing factors and external influencing factors.It was preliminarily concluded that the internal factors of slope deformation are mainly formation lithology and topographic factors,while the external influencing factors are mainly precipitation and human engineering activities.