As in the course of the extension of the Sydney Metro subway network a tunnel boring machine crossed under the existing City Circle railroad tunnels, Dibit Messtechnik GmbH was commissioned to carry out a detailed recording of the six tunnels in each case before and after the undercrossing. The aim was to determine surface changes and deformations by means of recording 270° of the tunnel inner shell.
The evaluated high-resolution 3D models of the different measurement epochs were globally georeferenced and can be compared with pixel accuracy in the Dibit8 software. Changes in the tunnel surface (cracks, spalling) as well as changes in the tunnel geometry (deformations) can be detected.
The client was provided with both the textured 3D models in open file formats and a Dibit8 software license for further analysis.