The hydro power plant Opponitz is undergoing renovation work which includes the rehabilitation of the existing, 2600 m long Opponitz penstock tunnel between Haselreith and the surge chamber in Opponitz. The main rehabilitation measure consists of a GFK Inliner, which will be placed directly onto the existing tunnel lining. To verify the tunnel dimensions for the GFK Inliner, a tunnel scanner survey was performed beforehand. The results provided the necessary information for dimensioning the rehabilitation measures.
All tunnel survey work had to be done within a very limited time frame to ensure that the tunnel could be re-flooded on time. Further time restrictions caused the fact that surveying work had to be coordinated with a structural inspection, which was performed at the same time.
Dibit Messtechnik GmbH services included to install a reference system in the tunnel. Therefore a traverse was measured through the tunnel with control points which were installed in increments of 50 m. All of the points coordinates were determined and tied together to form the reference system. Once the control points were in place, the tunnel scanning survey was carried out to geometrical and optical acquire the entire tunnel vault, resulting in a comprehensive, true color textured 3D model of the Opponitz penstock. From the 3D model, ortho-photos, in-situ and condition plans incl. tunnel objects, defects and stations of the segment joints were generated. In addition, a static profile analysis was accomplished between the actual and the design profile. Furthermore, horizontal and vertical cross sections, as well as point clouds with color information have been submitted to the client.