A NEW CONSTITUTIVE CREEP-DAMAGE MODEL FOR SALT ROCK AND ITS CHARACTERISTICS

摘要

A new constitutive creep-damage model for salt rock established by means of application of damage and a concept of "damage accelerating limit" into Carter's creep model is presented. Verification of the model is carried out based on the creep tests for salt rock. The results showed that the constitutive model not only gave a faithful representation of the creep-damage behaviour for salt rock under high stress, but also described efficiently the primary and stationary creep at low stress. Beyond the damage accelerating limit, the tertiary creep will occur, which influences strongly the damage evolution and creep. Furthermore, no great variation of the parameters describing the creep-damage behaviour by variant sorts of salt rock and by different test conditions was found. Therefore, the application range of the model is wide. Finally, some parameter studies were carried out and the essential characteristics of the model were investigated.