Computed and measured responses of a thick-walled hollow cylinder of salt subjected to both homogeneous and inhomogeneous loading

The present evaluations are based on comparisons of measurements on the hollow cylinders with predictions from three different constitutive models for rock salt. The three models are (1) an elastic power-law secondary creep (ESC) model, (2) a revision of the ESC (RESC) model with greatly reduced elastic moduli but unchanged creep parameters, and (3) a unified creep plasticity (UCP) model. The ESC model produced the predictions that differed from the Waste Isolation Pilot Plant (WIPP) in situ measurements by the factor-of-three or more. The modulus reductions in the RESC model are empirical adjustments that produced matching closures and closure rates with the WIPP measurements collected over less than five years. The UCP model yielded closures that were substantially higher than the ESC predictions but still less than the in situ measurements. At the same time, the UCP model produced closure rates in good agreement with the data. 12 refs., 5 figs., 1 tab