Identification Of Subway Tunnel Lining Diseases Based On Mobile Laser Scanning Technology

With the rapid development of the city,the subway plays an increasingly important role in the transportation of the city.At the same time,the number and scale of the construction of the subway is also increasing.The safety of the tunnel lining disease detection is under great pressure.challenge.The mobile 3D laser scanning technology breaks through the traditional manual detection and other manual measurement methods,and has the advantages of high precision,high efficiency and comprehensive detection.In view of this,this paper focuses on mobile laser scanning technology,from point cloud data processing and application analysis,researches the key technical papers of mobile laser scanning technology applied to tunnel lining disease detection.The main work of the thesis is as follows:1)According to the method of using fixed 3D laser scanner in tunnel measurement,the shortcomings are analyzed,the mobile laser scanner and its advantages are briefly introduced.The error source analysis was carried out according to its working mode and acquisition principle,and the specific methods for eliminating or weakening the error were discussed.2)Briefly introduce the data acquisition process of mobile laser scanning system,and analyze the quality and characteristics of point cloud data.3)According to the theoretical analysis of point cloud data characteristics and application requirements,the corresponding data processing flow is formulated.4)Combining a variety of easy-to-access software,the point cloud data processing scheme was studied,and the lining plane development map required for tunnel lining disease detection,as well as the locomotive limit and continuous tunnel cross-section point cloud required for the boundary measurement were verified.Data processing solution is feasible.5)The processing method of tunnel lining image is studied,and the automatic identification and calibration of tunnel lining diseases are realized.The disease statistics of the lining surface were studied.After the statistical analysis of the multi-stage disease,the conclusion that the tunnel lining disease growth slowed down and the health condition stabilized was obtained.The limit measurement method based on point cloud of tunnel cross section is studied,and multi-point and comprehensive limit measurement can be obtained.