Deformation Monitoring Of High And Steep Slope In Open Pit Mine Based On LiDAR DEM And Time Series SAR

In the process of open-pit mining,with the increasing depth,most of them are changed to deep concave mining.The formation of high and steep slope increases the maintenance cost and threatens the safety production.Therefore,it is very important to monitor the stability of the slope.Once the slope is unstable and landslide occurs,it will cause great losses.At present,the technology applied to mine slope deformation monitoring is developing continuously.With the development of radar satellite and the accumulation of data,SAR data has been successfully applied to deformation monitoring.For the deformation of mine slope,it is generally considered that the deformation direction is along the slope direction.However,at present,based on SAR data,pixel offset tracking(POT)technology is generally used to monitor large-scale deformation to obtain line of sight(LOS)and azimuth(Az)deformation variables.Time series InSAR(Interferometry Synthetic Aperture Radar)technology is often used for slow and small-scale deformation monitoring.However,Az and LOS deformation can not directly reflect the real sliding state of slope.Therefore,how to recover the LOS and Az deformation from the time series SAR data to the real deformation is the key problem in slope stability monitoring.In order to solve this problem,this paper proposes a high-precision digital elevation model(DEM)based on laser scanning,and uses the SAR monitoring results to retrieve the slope aspect variables.Based on the aspect data provided by high-precision DEM,LDAPOT(LIDAR DEM assisted POT)method is proposed to transform the monitoring results of POT into aspect variables;Based on the slope and aspect data provided by high-precision DEM,the LDASBAS(LIDAR DEM assisted SB AS)method is proposed to solve the shape variable of mine slope aspect by using the monitoring results of SB AS.The two schemes are applied to the monitoring of mine slope and the accuracy evaluation is carried out.In the long-term deformation monitoring of Fushun West open pit coal mine from March 2014 to the end of 2020,the deformation of Nangang landslide was large before 2017.The slope deformation was obtained by using Az LOS to slope deformation method.Compared with GPS data in the same period,the average error reached the sub meter level.The deformation of the southern bank is relatively slow in 2017-2020.The slope deformation is obtained by SBAS LOS to slope deformation solution method.Due to the phase unwrapping,SAR band and resolution of SBAS method,rapid deformation cannot be obtained.Therefore,although the results are the same as the measured data,the determination coefficient R2 can reach 0.9,but the relative root mean square error(RMSE)is relatively large,about 20%.The deformation scale of Dagushan Iron Mine is smaller than that of coal mine,so the slope deformation is also obtained by this method.Compared with the measured data,the RMSE of the rising rail data is about 13%.The relative RMSE of the data of the lowering track is about 6%,R2 is as high as 0.95.The results of this paper fully consider the terrain fluctuation,engineering geological conditions and precipitation of open-pit mines.The collaborative research of deformation monitoring methods is selected according to different slip characteristics,which can provide technical support and theoretical basis for long-term and high-precision monitoring of landslide disaster in open pit.