Creep law to describe the transient, stationary and accelerating phases

摘要

The proposed combined salt creep law describes the deformation-hardening behavior of the transient creep phase, which gives a good description for a relatively short time after the excavation phase and can, by considering the recovery of the hardening, also be extended to the stationary creep phase, which is significant for long times after the creation of openings. The developed material law also includes inverse transient creep, which takes place during load reductions. The accelerating creep phase is included by extending the material law through the accumulation of micro-cracks that come about depending upon the damage work performed. The dilatancy linked to that acts as an inner state variable.