Research On Rock Movement Observation In Mining Area Based On UAV 3D Laser Scanning Technology

It is an important work to explore the high-tech monitoring methods of surface subsidence in mining area to promote the safety production of mining subsidence.Traditional monitoring methods are not only time-consuming and laborious,but also difficult to meet the needs of production in some complex terrain conditions and difficult for people to pass through.UAV 3D laser scanning technology is a new low altitude 3D space measurement technology,which combines the advantages of UAV aerial survey and airborne 3D laser scanning system.Through the obtained point cloud data,the digital elevation model is constructed and the subsidence information is extracted to obtain the three-dimensional data of the land subsidence in the mining area.The accuracy of land subsidence monitoring by this technology is evaluated by using the measured bench marks in traditional surveying and the data of existing GPS monitoring stations.The research results show that the UAV 3D laser scanning monitoring technology can meet the needs of three-dimensional monitoring of mining subsidence.It has the characteristics of flexible,low-cost,high-efficiency and high-precision,and can be applied in similar areas in the future.The main research work of this paper is as follows:1.The research status at home and abroad is summarized and analyzed.In view of the shortcomings of traditional measurement methods,the UAV 3D laser scanning technology is applied to mine subsidence monitoring,and the research ideas and technical route of this paper are planned.2.The filtering method of Airborne LIDAR point cloud is studied.The traditional filtering methods are analyzed.Aiming at the shortcomings of the traditional Irregular Triangulation Network filtering algorithm,the first filtering is based on the echo times and reflectivity,and then the improved progressive encryption triangulation filtering algorithm is used to filter again.Finally,the accurate separation of surface points and non surface points is realized.Through the experimental analysis,the algorithm makes up for the shortcomings of traditional triangular network filtering algorithm,reduces the amount of calculation,and enhances the filtering effect on low vegetation.3.Build digital elevation model.Through the experimental analysis,the optimal point cloud density of DEM is constructed to reduce the amount of calculation and ensure the integrity of DEM.Through the comparison and analysis of DEM Interpolation Methods and the existing survey data,the accuracy evaluation of the constructed DEM is carried out.Finally,it is verified that the UAV 3D laser scanning system can meet the accuracy requirements of rock movement and settlement observation in mining area.4.Rock movement data processing and analysis.The terrain factors of the survey area are extracted by the generated DEM,and the distribution of slope and aspect can be seen directly.The section information of point cloud is extracted and compared in multi periods to analyze the change of profile.The plane accuracy is evaluated by the relative calibration of three periods of data,which not only checks the repeatability accuracy,but also checks the relative accuracy.The contour line is generated by point cloud and displayed in combination with digital elevation model.The elevation distribution of the survey area can be seen more intuitively,and the accuracy of DEM can be analyzed at the same time.By comparing the DEM generated from multi period point cloud data,the distribution of subsidence area in the survey area is obtained.