A damage-plasticity model for cohesive fractures

•The effects of damage process in rock joints behavior and rock slope instability are underlined.•A model combining plastic deformation and damage process in rock joints and cohesive cracks is proposed.•It is shown that the model reproduces well the main features of elastic-plastic and damage behavior of cohesive fractures.•The model has been validated by comparison to several sets of experimental data.

A model for the elastic-plastic deformation and damage process in rock joints and interfaces in quasi-brittle geomaterials is proposed. A close analysis of damage process in interfaces in quasi-brittle geomaterials, represented in cohesive crack models, shows that these models represent well also the damage process in rock joints. The commonly used non-linear elastic-plastic models of rock joints are completed by this damage process and extended to a general model for cohesive fractures which cover rock joints and cohesive cracks. This model reproduces well the main aspects of deformation and damage of cohesive fractures observed experimentally, namely, a non-linear elastic behavior before the stress peak, softening and decrease of the tensile and shear strengths with post-peak deformation, stiffness reduction after stress peak, general trends of irreversible relative displacements and existence of a residual stiffness in ultimate state under compression and shear. This model was fitted to several series of experimental results obtained on different geomaterials and a satisfying agreement between the model and experimental data was obtained.