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Title: Advances in resolution of discrepancies between predicted and measured in situ WIPP (Waste Isolation Pilot Plant) room closures

Technical Report ·
DOI:https://doi.org/10.2172/5784434· OSTI ID:5784434

An extensive reevaluation has been made of several major aspects of the simulation of the structural response of salt to improve the ability to represent actual deformations. As a result of the effort, it is now evident that the Tresca flow potential represents the behavior of salt. The previously used von Mises flow potential does not appear to be appropriate. The multimechanism steady state, workhardening/recovery transient (M-D) model now has been modified to be more representative of salt creep. Reevaluation of material parameters, based on new creep data and a better conceptual understanding of construction of the virgin state parameters has resulted in significant improvement in the material parameters available for calculation. In addition, reevaluation of the coefficient of friction on clay seams was found necessary. Actual underground observations also suggested a revised stratigraphic sequence at the WIPP facility horizon. The combination of the above improvements, when incorporated into a numerical simulation of the closure response of an underground test room (Room D), produced excellent agreement between calculated and measured closures. The agreement between the calculated and measured vertical closures is within 2% for the nearly 4.4 years represented by the experimental data. Agreement between the calculated and measured horizontal closures is not quite as good, with the calculation overpredicting the observed closure by 18%. However, based on these calculations, the approach presented here appears to have resolved much of the earlier discrepancy between calculated and measured closures. 56 refs., 22 figs., 2 tabs.

Research Organization:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
DOE Contract Number:
AC04-76DP00789
OSTI ID:
5784434
Report Number(s):
SAND-88-2948; ON: DE89015193
Resource Relation:
Other Information: Portions of this document are illegible in microfiche products
Country of Publication:
United States
Language:
English