Creep behavior of bedded salt from southeastern New Mexico at elevated temperature

Abstract

Nos. 02-8B58and 05-7466). 1.The collected data included axial and lateral strain, axial and confinement stresses, time and temperature. Periodically, axial stress was adjusted to account for specimen strain in order to maintain a constant differential stress. Frequency of the stress correction was dependent on the rate of deformation; two or more corrections in a 24 hour period were typical. Data were automatically recorded with a printer, manually receded from the print-out to punched cards and reduced by means of a computer. A preponderance of the data (see Section 4.1) was collected in the transient creep regime. In some tests specimen rupture occurred, while in others an accelerating creep rate brought the specimen in contact with the pressure vessel wall. Also, a considerable amount of data was collected during stress application to creep stress level. It is the purpose of this report to present all of the data obtained in a concise manner such that use can be made of these results by Dr. Wawersik in his more comprehensive experimental program. For that matter, the contents have been divided into sections which present summaries of the collective results. The experimental data have been fit with equations which describe transient creep. All of the data is presented in plots in the Appendices. Considerable attention was also given to specimen characterizationand measurements after deformation. 10* The prefix UT denotes untested specimen. The saffix (A) or (B) differentiates between specimens recored from the same depth. ** Approximated, DC'DT temporary malfunction.

WIPP shaft seal system parameters recommended to support compliance calculations

“…Laboratory testing of salt cores has also provided significant insight into DRZ development. Hansen and Mellegard (1979) found that dilatancy is favored by conditions of low-confining stress and high deviatoric stress which characterize the region near an excavation. Laboratory testing has shown that a halite DRZ is self-healing given the proper stress conditions (Brodsky, 1990).…”

Salt disposal of heat-generating nuclear waste.

“…Extensive research has been conducted in the laboratory to determine both the deformational and hydrological behavior of natural salt. Early work focused on the characterization of the elastic and inelastic viscoplastic flow properties of salt (e.g., Hansen and Mellegard 1977, Wawersik and Hannum 1979, Hansen and Mellegard 1980, Senseny 1986, Mellegard and Pfeifle 1993. Most of the early studies provided parameters for the constant-volume creep model, which was validated against large-scale thermal-mechanical experiments.…”

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“…Quasi-static properties were generated over a range of l o a d i n g rates frm d/dt -0,) of 150 t o 215 psi/min (RE/SPEC Inc. data, Gnirk e t al., 1973, Hansen andMellegard, 1977) to l o a d i n g rates of 30 to 60 psi/min (Sandia data, Wawersik, 1977, 1 9 7 8~) . The 30 psi/min loading rate was chosen to match t h a t of published data (Dreyer, 1972, Menzel andSchreiner, 1977).…”

“…Tests d u r a t i o n s vary between 0.5 and 500 hours (Hanson, 1977, andHanson andMellegard, 1977). I n i t i a l efforts served to e v a l u a t e t h e s i g n i f i c a n c e of t r a n s i e n t creep on t h e p o s s i b l e r e p o s i t o r y c o n d i t i o n s , t o e s t a b l i s h upper (conservative) bounds for s t e a d y state creep rates a t r e l a t i v e l y low d e v i a t o r stress and temperature, and to test t h e a p p l i c a b i l i t y of a p i l l a r creep formula w h i c h has been widely used (Bradshaw and McClain, 1971) :…”

“…On F i g u r e 9.2.4-18, photographs of core samples from ERDA #9 are shown t h a t were deformed during triaxial t e s t i n g ( Hansen and Mellegard, 1977). N o t i c e t h e l a r g e amount of s t r a i n test N u m b e r s 6 and 7 have undergone without apparent major p h y s i c a l damage.…”