Fluage du sel gemme sous très faibles charges

Long-term creep tests have been performed under very small uniaxial loadings ( σ = 0.02 to 0.1 MPa). Testing devices were set in an underground gallery, where temperature fluctuations are in the order of one hundredth of a Celsius degree. The mechanical loading was provided by dead weights. The displacements were measured through special sensors whose resolution is Δ ɛ = 10 −8 . Strain rates as small as ɛ ˙ = 10 −12   s −1 were measured. The tests prove that constitutive laws deduced from tests performed on rock salt samples under standard mechanical loadings cannot be extrapolated to very small loadings. To cite this article: P. Bérest et al., C. R. Geoscience 336 (2004).