Analysis of the failure mechanisms of a weak rock through photogrammetrical measurements by 2D and 3D visions

This research has been dedicated to the experimental study of two different types of marls through uniaxial compressive tests on prismatic specimens. Induced deformations were measured during testing by classical extensometers and by means of photogrammetrical measurements. Either one or two cameras were employed to allow, respectively, 2D or 3D (using a stereoscopic vision) displacement measurements. A specific software was developed and applied to determine displacement and deformation maps at each photogram on the whole specimen surface. The interpretation of experimental tests, carried out for a better understanding of failure phase in weak rock before crack propagation starts, is illustrated in the paper.