[en] The work presented in this paper was guided by the need of getting reliable mechanical informations on rocks and their potential use by numerical codes for modeling. For this purpose, a polyaxial compressive test apparatus completely driven by a micro-computer has been built; and the data supplied by this system are treated numerically to find the desired characteristics. A lot of tests have been achieved on two carbonates. We have investigated the changing in the behaviour of the rocks when the confining state increases: change of the rheological model and evolution of the mechanical properties. We have also built tridimensional envelopes at failure and tried to set some constitutive laws using a modified Mohr-Coulomb criterion.
