Research On Quality Inspection Method Of Shield Segment Assembly Based On Point Cloud Data

With the rapid development of shield construction technology,the quality of shield construction has attracted extensive attention.In order to improve the quality of construction,the quality inspection of segment assembly is taken as the object of the study.The dislocation and ovality are selected as the quality evaluation indexes.Then the quality management system is constructed.Based on the analysis of the shortcomings of the traditional detection methods,the implementation of the quality inspection of segment assembly molding based on point cloud processing is proposed.Then,a algorithm for calculating the dislocation and deformation based on point cloud processing is designed,and the feasibility of the algorithm is verified by an engineering example.The research contents are as follows:Firstly,the concept and management system of segment assembly quality are introduced in this thesis.The conclutions are as follows: 1)dislocation and deformation are the cause of assembly nonstandard,shield posture failed to adjust,grouting quality is poor;2)segment assembly quality management including quality inspection and quality control,the results of quality inspection can serve as a strong basis for quality control;3)the traditional detection method is low and time-consuming,and it is difficult to meet the needs of the project.However,the 3D laser scanning technology can make up for deficiencies to some extent.Secondly,the implementation process of quality detection based on point cloud processing,including data collection,using the software of registration and removing noise treatment,design algorithm of dislocation and deformation index extraction.The algorithms,carried out in this thesis,include pre-processing of the cloud data,dislocation algorithm and the ovality algorithm.The pre-processing of the cloud data including coordinate transformation,accurate denoising,line extraction and circle fitting can simplify calculations and increase speed.The dislocation and ovality caculation is designed according to the geometry of the tunnel,and is suitable for practical engineering.Finally,the 103 rd rings to 107 th ring eighth section of Wuhan Metro Line 7 project is taken as the object.The feasibility of the algorithm is checked and the field review is given to show that the algorithm can improve the detection efficiency under the condition of satisfying the accuracy.