DEFORMATION MECHANISMS OF WIPP BACKFILL

Experimental studies of densification processes and mechanical propert ies of crushed rock salt have been conducted. Increases in Young's mod ulus, unconfined compression strength, and inelastic deformation with respect to densification time have been observed. Gradation effects on the densification rate of crushed rock salt are reported. Permeabilit y of densified crushed rock salt has been studied using the continuous flow rate of gas method. A continuum healing mechanics model is propo sed within a framework that automatically meets the restrictions of th ermodynamics. Both rate independent and rate dependent formulations ar e given. Specific evolution equations are given for a scalar isotropic assumption and good correlations are shown for changes in time of You ng's modulus, inelastic strain and density.