Preliminary Deformation-Mechanism Map for Salt (With Application to WIPP).

摘要

Through the use of theoretical and experimental results, a complete but preliminary deformation-mechanism map for salt is constructed. This map shows those mechanisms,and consequently the constitutive equations,which control the deformation of salt for all imposed conditions of stress and temperature. Five mechanisms are identified as relevant. There are defect-less flow,dislocation glide,dislocation climb creep (two variations),diffusional creep (two variations),and an undefined mechanism. When the envelopes bounding relevant experimental investigations are overlayed on the map,it is possible to determine the interplay between data. This perspective permits a more rational interpretation of high temperature creep data. The most powerful use of the map stems from an overlay of possible stress and temperature conditions of the Waste Isolation Pilot Plant, A proposed radioactive waste isolation project in bedded salt. It is also possible to draw from the map some general conclusions about data adequacy and constitutive equation forms that would pertain to the project from the map. Moreover, a first-cut constitutive equation for deformation of salt for the project conditions is formulated based on empirical knowledge and the two important mechanisms. The proposed equation incorporates the effects of the transient creep response and of the transition activation energy. (ERA citation 04:021815)