Mechanical behaviour of Darney sandstone (Vosges, France) in biaxial compression

Abstract The mechanical behaviour of Darney sandstone (Vosges) was studied in biaxial compression with equipment which enables a large area of uniform loading to be obtained by elimination of extraneous flexion torque and by limiting friction at the contact surfaces. Strains in the three principal directions were measured throughout the tests performed up to the failure. Slight anisotropy of the material is shown by the stress-strain curves. The failure surface trace in the stress plane can be considered, to a satisfactory approximation, as an ultimate iso-strain ϵ 3 (strain in the non-loaded direction). The maximum extensional strain criterion expressed in terms of ϵ 3 is concluded to be the appropriate failure criterion.