A continuum damage mechanics approach for time independent and dependent behaviour of brittle rock (Q1352673)

The nonlinear deformation of a sandstone is investigated. Short term triaxial tests and creep tests have been performed in order to study the short term behaviour (instantaneous growth of cracks) and the time-dependent behaviour (subcritical growth of cracks) of the rock. A continuous damage model is proposed, where the internal damage variable is directly related to the second order crack density tensor. Two crack growth criteria (instantaneous and subcritical) are used to describe the time-independent and time-dependent evolution of the damage tensor. The verification of the model is presented for various loading paths. Good agreements between experimental data and model's predictions are obtained.