A Micromechanical Model for Time Dependent Behavior Related to Subcritical Damage in Quasi Brittle Rocks

摘要

In France,an underground research laboratory is constructed in a clay formation,called Callovo-Oxfordian argillites.In order to evaluate quantitatively the structure durability,it is necessary to achieve a good understanding of the long-term behavior of the material.Subcritical crack growth is one of main causes of time-dependent behavior in rock.In order to rigorous modeling of the time-dependent behavior of studied material,a micromechanicai model incorporated subcritical damage propagation is proposed for Callovo-Oxfordian argillites in this paper.In the proposed constitutive model,the argillite is considered as a two phase composite:the clay matrix and the mineral inclusion.Based on experimental observations [1],the clay matrix is described by a time-dependent damage model and the mineral inclusions are described by a linear elastic model.The passage from the micro-scale to the macro-scale is done through different homogenization schemes for studying their influences on the subcritical propagation of cracks.