Study On Slope Deformation Monitoring Of Open-pit Mine Based On Ground 3D Laser Scanning

The ground 3D laser scanner can directly obtain the high-precision,high-density spatial three-dimensional coordinates of the surface,that's point cloud data,without touching the object to be measured,and then processing it to constructing a high-precision,high-resolution three-dimensional digital model.Therefore,it is widely used in slope deformation monitoring.This paper introduced the ground 3D laser scanner in detail.Based on the analysis of open-pit mine slope monitoring data and the analysis of the results after processing,this paper explored the theory and method of the monitoring of the deformation of open-pit mine slope based on the ground 3D laser scanning.In this paper,point cloud data of surface mine slope obtained by surface 3D laser scanner is taken as a sample.Riscan_Pro and Geomagic software are used to research the data registration method and deformation monitoring and analysis methods for multi-site data of slope.First of all,select the instance data to analyze different point cloud registration methods,and combine the measurement robot technology to evaluate the accuracy and find out the best registration method for cloud data of mine slope point.Secondly,according to the actual natural topographic features of the slope in the study area,corresponding deformation monitoring and analysis experiments are carried out on the slope surface,line,and point features.Finally,the close-range photogrammetry monitoring technology was used for comparative analysis and verification to complete mine slope deformation monitoring research.The main work and results are as follows:First of all,research on point cloud registration method.Feature-based point cloud registration method is not suitable for large-scale mine slope point cloud data obtained by longdistance scanning,and the GPS_RTK registration method can effectively splicing the slope multi-site cloud and directly convert it into the actual engineering coordinate system,In addition,the accuracy of GPS_RTK registration is higher than that of feature-based point cloud registration in combination with measurement robot technology under existing open-pit mine conditions,and its registration efficiency and operation simplicity are better than other methods.So this paper chooses GPS_RTK point cloud registration method as the best method of experiment.Secondly,based on the data of slope point cloud,the method of slope deformation monitoring was studiedby three methods:overall DEM superposition analysis,slice superposition analysis and contour line coincidence analysis of multi-temporal slope.The results show that the slope shape variable shows a polarization phenomenon,which is divided into a landslide area and a stable area according to the degree of local slope performance.The coincidence analysis chart of the deviation chromatogram,deviation value and adjacent contours shows that the southern end of the experimental area is close to the location of the mining area occurred in the second(July),fourth(September)and fifth(October)landslides.Among them,the overall 3D maximum deviation in the second phase is 5.0944 m,the maximum deviation in the horizontal axis(Z=70m)2D is 2.8692 m,and the vertical axis slice(Y=1220m)in the landslide area is the largest deviation in 2D is 2.8781 m,the standard deviation is 1.0118m;the overall maximum 3D change in the fourth phase relative to the third phase is 2.7146m/-2.4269 m,the cumulative maximum deviation is 5.0587 m,and the change in the horizontal slice(Z=50m)is greater than the horizontal slice,2D the maximum deviation is 1.3275m;the overall deviation of the fifth period exceeds the critical range of 0.5254% of the total value,the maximum cumulative deviation is 7.7480 m,the maximum 2D deviation of the transverse section is 2.8576 m,and the maximum 2D deviation of the vertical slice(Y=1220m)is 2.8256 m,the standard deviation is 0.8753m;while in the stable region,the vertical axis slice(Y=1500m)is basically in a constant state throughout the cycle,with a standard deviation of a minimum of 0.0023 m and a maximum of 0.0059 m.Finally,based on the image information obtained from photogrammetry and the coordinate information of the image control point collected by the robot,three methods for simultaneous analysis of the overall DEM superposition,slice superposition,and the corresponding monitoring point change trend of the multi-temporal slope are used.Slope deformation monitoring results are compared and verified.The results show that the distribution of point cloud within the overall phase-to-period corresponding error range is basically the same,the proportion of point cloud within the same range of error within the same period remains basically the same,and the changes are similar;for the same position slice analysis,the 2D maximum deviation at the left end of the second horizontal axis slice is 2.7768 m at-the southern end of the study area,corresponding to 2.8692 m at the same position in the laser scanning technique,and the 2D maximum deviation and standard deviation of the vertical axis slice(Y=1220 m)are 2.8701 m and 1.1122 m respectively,corresponding to 2.8781 m.and 1.0118 m,landslides occurred.The maximum 2D deviation of the horizontal slice at the fourth stage was 1.4342 m,corresponding to 1.3275 m at the same position.The slice change at the fifth horizontal axis was greater than that at the lower slice.The maximum 2D deviation and standard deviation were respectively,landslide occurred at 2.8631 m and 1.0126 m corresponding to the same slice of 2.8256 m and 0.8753 m.Analysis of the vertical axis slice(Y=1500m)in the stable area showed that the maximum change position was not the same,but the bias value and the basically stable and consistent trend are in line with the results obtained by the laser scanning technology.Finally,from the representative A001-A010 monitoring point three-dimensional coordinates and point period cycle trend map comparison shows that in the two technologies in the landslide area A001,A005,A009 and A010 monitoring points show a basically consistent results of the change trend,The point A006 in the stable area but close to the edge of the landslide area was affected by the landslide in the fifth period with a deformation of about 0.4m,while the monitoring points of the A002,A003,A004,A007 and A008 in the stable area were basically stable,further the feasibility and accuracy of ground surface 3D laser scanning technology in the deformation monitoring of open-pit slopes are verified.