3D images for digital geological mapping - Focussing on conventional tunnelling

3D images combine visual and geometric information making them an obvious source for capturing and characterising rock surfaces especially when there are constrained time and access conditions. By taking photographs with an off-the-shelf camera and using modern algorithms from photogrammetry, 3D imaging has become state of the art on many conventional tunnel construction sites. Data is acquired on a daily basis, processed, geologically assessed, and finally stored in a suitable data base. The contribution provides a brief introduction of the technology and its measurement capabilities, as well as a description of the practical application during the construction of the 8 km long Gleinalmtunnel in Austria.