Etude comparée de la fracturation observable sur carottes de forage et obtenue par diagraphie. Application au marbre de Saint-Béat (Haute-Garonne)

International audienceThe structural analysis of a rock mass within the scope of a tunnel construction project entails, in most cases, conducting an assessment of the discontinuities present through use of borehole imaging techniques. This site surveying method is combined with other techniques in recording the entire set of rock mass characteristics. Such a highly-useful technique however carries with it some application limitations that need to be taken into consideration. To illustrate these remarks, we have relied upon the surveying campaign undertaken for the Saint-Beat Tunnel, in proceeding with a comparison of the discontinuities identified on a digital image of borehole walls and manually on core samples. We have highlighted the biases induced using these methods, and such biases must be incorporated in order to better characterize the geometry of the given fracture network