Research On Monitoring The Deformations In Construction Of Civil Engineering By 3D Laser Scanner

As another innovation of science and technology in the field of surveying and mapping,3D laser scanning technology with its unique advantage received extensive attention of the domestic and foreign scholars and engineers.The technology can obtain the target's 3D coordinate information with high precision,high density,high rate and no touch,having profound development prospects in many fields.Therefore,it has very high engineering value and theory significance to study the application of the technology to monitor architectural engineering which under construction.Applied to engineering examples,the working principle of 3D laser scanning technology and two point cloud pretreatment algorithms are introduced in detail in this paper;the characteristics of the technology and the main application field are summarized;the precision of the technology and its research status in the field of deformation monitoring are particularly studied;and two new monitoring methods based on 3D laser scanning technology are put forward.The main research contents and results are as follows:1.The research and development status of 3D laser scanning technologies are discussed,and the current research status of the technology in the field of deformation monitoring is emphatically analyzed.Although 3D laser scanning technology has been used in the aspect of deformation monitoring,it does not perfect enough to be able to show its advantages.2.The FARO X330 3D laser scanner and its supporting system,Total Station Positioning,are introduced in this paper.The distance measurement principle of the scanner is phase method,which ranging precision is plus or minus 2mm at 10 m and 25m;with TSP and high precision total station,the point cloud data can be processed into splicing effectively and absolute orientation with high precision.3.Based on the test of precision inspection by Total Station Positioning,the FARO X330's ranging precision is correspond its nominal precision basically.According to the analysis of positional accuracy of scanner's,the positional accuracy is affected by ranging accuracy,angle measurement accuracy and the vertical angle,and the positional accuracy at 25 m is checked using the precision results.The origin of the errors of 3D laser scanner is analyzed,and several measures to reduce the error are proposed.4.In view of the deformation monitoring,the allochthonous control method based on 3D laser scanning technology and TSP control method are proposed.The scanner can finish deformation monitoring without the total station or GPS to measure the three-dimensional coordinates of the control points by allochthonous control method;TSP control method,making full use of the internal inclinometer sensors of the scanner,can achieve a high precision in the two phase of the point cloud registration.In order to study the precision of positioning of allochthonous control method and TSP control method,the simulated deformation test is designed.The results show that the accuracy of allochthonous control method is affected by single registration for 1-2mm,and the fewer the number of registration,the higher the precision.The accuracy of TSP control method is higher,but it is more easily affected by the precision of total station.5.The horizontal displacement,vertical displacement of palisade structure pile wall,the settlement of the roads surrounding foundation pit and the obliqueness of buildings around the foundation pit can be monitored by the scanner.When two monitoring methods respectively applied to engineering practice combining scanner,the monitoring results is reasonable.The advantages of the scanner in deformation monitoring are highlighted by the putting forward of the data processing methods,two points method and normal vector method which can be used for the analyses of the tilt of the structure.