CEE Seminar: Micro-Macro Damage and Healing Rock Mechanics

Damage and healing in rocks refer to variations of mechanical and physical properties induced by pore or crack evolution. The gap between microscopic and macroscopic models makes it infeasible to uniquely characterize the pore- and crack- scale mechanisms that control deformation, stiffness variations and strength changes, or to relate the crack rebonding time to the porosity and stiffness healing time. The goal of this research is, therefore, to understand and predict chemo-mechanical damage and healing processes in rocks, by coupling micro-scale thermodynamics to macro-scale poromechanics. Continuum Damage Mechanics allows predicting the evolution of distributions of micro-cracks and the consequent changes of macroscopic mechanical properties. In a reactive environment, crack propagation can be either enhanced or hindered by dissolution/precipitation and mass transport. To understand this interplay, it is possible to define the damage and healing tensors as moments of probability of microstructure descriptors, or to homogenize the behavior of interacting inclusions that characterize the microstructure. In the former approach, the model needs to be informed and calibrated by sequential microstructure images. In the latter approach, it is expected that microscopic balance equations and constitutive laws are known. In both cases, models are validated against macroscopic stress/strain curves and porosity measurements. We restrict this talk to chemo-mechanical damage and...