This case study presents a high resolution 3D imaging and assessment system and its application during the construction of a planned nuclear waste repository in Hungary. During the drill and blast excavation of two inclined access tunnels of about 1.800 m each the system is applied on a regular basis (every round) in order to support the underground exploration program. From the acquired 3D images thorough geological mapping is performed as the system allows directly measuring geometric information on visible discontinuities such as dip and dip direction. The major benefits of the described system in this project are: (i) comprehensive, objective, three-dimensional records of the actual rock mass conditions, (ii) thorough rock characterisation by directly measuring geological features on the computer, (iii) increased safety for geological mapping due to the contact free measuring principle, and (iv) advantageous referencing mechanism using panoramic images.
The safe storage of radioactive waste is a topic of interest not least due to the constant accumulation of the problematic material. Sites already in operation such as the first one - the Waste Isolation Pilot Plant in New Mexico - or under long-term exploration such as Yucca Mountain (both USA) demonstrate that underground storage of radioactive waste is an issue. Before and during the construction of an underground site, data acquisition on ground conditions is essential to ensure amongst others long-term stability of the structure. Especially during construction works the continuous collection of information on the rock such as type, structure, and quality, as well as the system behaviour requires special attention (Schubert et al. 2003). Relevant parameters particularly important for rock mass modelling are related to discontinuities, such as orientation, spacing, frequency, size, aperture, filling width, termination index, or the georeferenced position, as well as the rock surface geometry (Priest 1993).