Research On Method Of Building Deformation Monitoring Based On 3D Laser Scanning Technology

During the construction and use of a building,the stability of the building is affected by many factors,both internal and external,and it is prone to deformation phenomena such as settlement,tilt,and displacement.It is of great significance to carry out periodic safety monitoring.At present,traditional deformation monitoring methods have problems such as single data processing form,long monitoring period,difficult monitoring point arrangement,and large workload.This paper uses the advantages of 3D laser scanning technology such as fast,high-density,high resolution,and noncontact technology,to introduce it into the field of building deformation monitoring.A fast algorithm was used to take the point cloud data of the tower structure of the Wuhan Erqi Changjiang River Bridge as an engineering example.The application of the linear characteristic point cloud data of the cable stayed cable and the characteristic point cloud data of the main tower was studied in deformation monitoring.The main work done is:(1)The factors affecting the measurement accuracy of the 3D laser scanner are analyzed,and the influences of the distance measurement,angle measurement and the error generated by the target reflective surface are deduced in detail,and some improvement measures are proposed.(2)Aiming at the characteristics of point cloud data,such as large amount of data,high redundancy,disorder,etc.,an improved feature extraction algorithm of point cloud data is proposed.According to the comparison results of the examples,it shows that the algorithm can extract the outline of the point cloud data clearly and completely.At the same time,it also has a good effect on the extraction of internal details.Comparing with the existing algorithms,the algorithm runs fast,features fewer broken lines,more complete feature contours,and fewer redundant points.(3)The slope monitoring of buildings was studied.Based on the idea of straight line fitting in numerical analysis,a method for building inclination monitoring using the characteristic line of building point clouds was proposed.This method will extract the external outline of the building.The characteristic line is a 3D linear least-squares fitting.According to the parameter value of the smoothed straight line function obtained after fitting,the inclination angle and inclination rate of the characteristic line of the building contour are judged,and the external contour feature fitting line measured at different times is compared.The tilt rate determines the inclination of the target building.(4)Taking the point cloud data of the towers and the cable-stayed buildings of the Wuhan Erqi Changjiang River Bridge as an example,the five-phase scan data obtained from different periods before and after the monitoring are used to obtain the cloud points of the buildings scanned at different phases on the CloudCompare software platform.The feature data were compared to extract deformation information,and the overall displacement variation of cable stays,the level of towers and displacements of settlements,and the trend of tower tilt were obtained.By comparison with the overall point cloud data,the feasibility of this method is verified.Through the above research,it provides a certain method for the application of 3D laser scanning technology in the field of building deformation monitoring,highlighting its advantages for the deformation monitoring,because the research in this area is not yet complete,has a certain practical significance and research and development space.