Research On 3D Deformation Monitoring Using Time Series InSAR For High And Steep Slope Of Open Pit Mine

Long term mining has caused ground subsidence,landslides and other geological disasters,which have become an important factor threatening the safety of people’s lives and property and affecting regional economic development.It is very important to monitor and analyze the long time series and large gradient surface deformation caused by such major geological disasters.Small baseline subsets(SBAS InSAR),which was developed at the beginning of this century,is affected by the geometry of radar observation.The results of SBAS InSAR can only reflect the one-dimensional deformation of ground objects along the line of sight(LOS)of radar,and can not obtain the real three-dimensional deformation field of the ground surface only by single technology and single platform.Offset tracking(OT)technology is based on SAR image intensity information,multi-level registration to obtain high-precision azimuth and range twodimensional surface deformation information,which can overcome the one-dimensional limitations of SBAS InSAR technology.However,compared with SBAS InSAR technology,the accuracy of OT technology depends on the resolution of SAR image,so without introducing external data,combined with SBAS InSAR technology and offset tracking technology to monitor the surface deformation,the real three-dimensional surface deformation field can be obtained only from SAR data.The sensitivity of different orbit SAR data in monitoring surface deformation is different,especially the reliability of landslide monitoring displacement results in mining area can not be quantitatively described.From the three-dimensional solution results,combined with SAR imaging geometry and slope aspect,the reliability of time series InSAR slope displacement monitoring results can be quantitatively evaluated.Based on long time sequence multi orbit SAR image,combined with SBAS InSAR technology and offset tracking technology,this paper studies two representative high and steep slopes in Fushun West open pit mine and Qidashan open pit mine.It mainly includes the following three aspects:1.Based on sentinel-1 SAR data source,SBAS InSAR technology and offset tracking technology are used to obtain the line of sight,azimuth and range deformation information of surface deformation in Fushun West open pit mine,The complete deformation informtion of Fushun West open pit mine in the second half of 2015 and the first half of 2016 was obtained.2.Based on the SAR data sources of sentinel-1 in two orbits from 2015 to 2016,offset tracking technology is used to obtain the line of sight and azimuth displacement of surface deformation in Fushun West open pit mine in the time range,so as to overcome the difficulties of limited data and multi-directional landslide in the study area,and horizontal track observation is used to solve the three-dimensional deformation field,Through the sensitivity factors of slope monitoring,the reliability of InSAR Technology in landslide monitoring in different directions is quantitatively evaluated.3.Using sentinel-1 SAR data of the study area and SBAS InSAR technology to obtain Los directional deformation variables,combined with InSAR monitoring results,GNSS monitoring results and high-precision DEM data,the sensitivity influencing factors of slope monitoring are calculated,and the relationship between slope displacement geometric characteristics and SAR observation geometry is analyzed and verified The availability and effectiveness of the satellite data in identifying and monitoring the southwest slope landslide of Qidashan Iron Mine are analyzed.