Very Slow Creep Tests on Salt Samples

Abstract

Long-term creep tests have been performed on rock-salt and argillite samples under very small uniaxial loadings 0.02 to 0.1 MPa. V To minimize the effects of temperature variations, testing devices were set in a mine where temperature fluctuations are of the order of one-hundredth of a degree Celsius. The mechanical loading was provided by dead weights. The deformations were measured through special displacement sensors with a resolution of 8 10. 'H Strain rates as small as 13 1 7 10 s H u were measured. These tests allow rock-sample creep to be investigated at very small strain rates. The tests also prove that extrapolation of constitutive laws at very small rates is often incorrect.

Rheological stratification in impure rock salt during long-term creep: morphology, microstructure, and numerical models of multilayer folds in the Ocnele Mari salt mine, Romania

“…As pointed out by Biot (1961), the dominant wavelength increases by a factor of m 1/3 for a multilayer composed of m layers. The relation is valid only for the case of a simple multilayer stack composed of alternating stiff and soft layers with equal thickness.…”

“…Understanding folding in multilayers is rooted in the analysis of deformation of an isolated more viscous layer embedded in the less viscous matrix. Biot (1961) and Ramberg (1962) described the wavelength selection process, which is responsible for the faster growth of selected wavelengths and leads to development of a semi-regular pattern of the fold train. The wavelength that initially experiences the largest growth rate is referred to as the dominant wavelength.…”

“…The wavelength-to-thickness ratio with the maximum cumulative amplification is referred to as the preferred wavelength. Further studies on the wavelength selection process allowed a relation to be established between the single-layer fold shape and the rheological parameters (Biot, 1961;Sherwin and Chapple, 1968;Fletcher and Sherwin, 1978;Schmalholz and Podladchikov, 2001).…”

“…Numerous theoretical (e.g. Biot, 1961Biot, , 1965Johnson and Fletcher, 1994), analogue (e.g. Currie et al, 1962;Ghosh, 1968;Cobbold et al, 1971;Ramberg and Strömgård, 1971), and numerical (e.g.…”

Nonlinear Elasto-Visco-Plastic Creep Behavior and New Creep Damage Model of Dolomitic Limestone Subjected to Cyclic Incremental Loading and Unloading

“…The time-dependent deformation characteristics of rock, especially the creep behaviors, are related to the long-term stability of underground rock engineering, such as tunnels and roadways [1][2][3][4][5][6][7][8][9][10][11]. Many scholars have carried out extensive research on creep mechanical behaviors of different types of rocks.…”