Modeling the viscoplastic and damage behavior in deep argillaceous rocks

摘要: In order to demonstrate the feasibility of a radioactive waste repository in Callovo-Oxfordian claystone formation, French national management agency (ANDRA) started 2000 build an underground research laboratory at Bure (East France). One key issues is understand long term behavior drifts. More than 400 m horizontal galleries main level -490 have been instrumented since April 2005. The continuous measurements convergence are available, allowing better understanding time-dependent response natural scale. Results indicate that viscoplastic strain rates observed undamaged area far from gallery walls same magnitude as those obtained on rock samples, whereas recorded damaged or fractured zone near one two orders higher, indicating significant influence damage or/and macro-fractures strains. Based these observations, macroscopic model which aims improve prediction EDZ proposed and implemented FLAC3D. Both instantaneous considered model. short assumed be elactoplastic with hardening/softening based concepts viscoplasticity (Lemaitre's model). Finally, damage-induced strains changes examined through plastic deformation (assumed approach rate). verify both constitutive equations their implementations, several simulations performed: (a) triaxial tests different confining pressures; (b) single- multi-stage creep tests; (c) relaxation total axial levels, etc. example blind excavation drift parallel minor stress, sh (gallery GED) presented compared situ measurements. results show advantages disadvantages this new discussed.