Research on method for measuring rebound rate of shotcrete in tunnels based on image 3D reconstruction
Aiming at the problem of how to quickly and accurately measure the rebound rate of shotcrete in complex tunnel construction environments,a new method for measuring the rebound rate of shotcrete in tunnels was proposed based on the main theories and algorithms in machine vision 3 D reconstruction technology.The method used coordinate markers and handheld cameras to quickly capture images,and based on the structure of motion recovery(SFM)algorithm,patch-based multi-view stereo(PMVS)algorithm,and triangulation principle,a three-dimensional surface mesh model of the actual excavation contour and initial support inner contour of the tunnel was established.By using the grid ray method,the spatial difference between the actual excavation contour of the tunnel and the three-dimensional mesh model of the initial support inner contour was solved to obtain the actual effective volume of shotcrete for the initial support.Finally,based on the actual total amount of shotcrete,the determination of the rebound amount of shotcrete was completed.Field tests and applications were carried out in the Badong tunnel of Zhengwan high speed railway.The results show that the rebound rate of shotcrete measured by the proposed method is more reasonable and accurate than that of the traditional field weighing method,indicating that the method can better achieve the rebound rate of shotcrete.In on-site application,combined with the test results of the rebound rate of shotcrete,suggestions for reducing the rebound rate in construction quality control is well constructed after being adopted on site,ensuring the quality of tunnel construction.The measurement method has the advantages of simplicity,efficiency,low cost,no interference with construction,and is of good engineering application.
tunnelshotcrete rebound rate3D image point cloudimage 3 D reconstruction
万方数据
维普
