Innovative management of geological data as a tool for safe tunnelling
The construction of a tunnel in hard or soft ground requires adaptation to the material provided by the prevailing geological conditions, whose history of origin, properties, three-dimensional structure and groundwater conditions all have to be taken into account. Geologists at the site work within a team of experts. Their job is to observe and to evaluate the encountered geological, hydrogeological and geotechnical conditions and record all the key parameters and influential factors, which were identified during the geotechnical design phase. Based on the field observations, the geologists give a prognosis of the further geological conditions for the future tunnel advance. Unknown and unfavourable geological conditions during tunnel advance carry extremely high risks for the whole excavation progress. Therefore, the prognosis must be given as accurately as possible to avoid dangers. Geological observations in underground constructions, such as tunnels, are almost exclusively spatial information and therefore must be recorded and analysed in three dimensions. In addition to the types and properties of ground encountered, the positional relationships of the geological bodies to each other and the discontinuity sets of the rock mass have a great influence on the stability of the underground structure. Therefore, powerful software tools were developed, which help the expert on the site to deal with the high amounts of data produced during face mapping and record the geological information in a 3 dimensional system. With this data basis it is now possible to generate a detailed prognosis of the geometry of geological structures with geostatistical methods. In the following paper, such a system is presented.