Numerical investigation of the couplings between strain localisation processes and gas migrations in clay materials

Deep geological repository is the preferred solution in many countries to manage radioactive wastes, such as France where Callovo-Oxfordian (COx) claystone candidate host rock. In clay rock formation, drilling of storage gallery creates an Excavation Damaged Zone (EDZ) with altered flow properties short term, while corrosion processes release large amounts gas long term. Assessing evolution pressures near-field and predicting effect EDZ on transport remains a major issue. This paper presents second gradient two-phase hydro-mechanical (H2M) model tackling multi-physics couplings related transfers fractures development. The reproduced by shear strain localisation bands using microstructure enriched approach. migration captured biphasic fluid transfer model. impact fracturing addressed relating permeability water retention curve mechanical strains. Using this tool, numerical modelling drift COx performed aim emphasising influence HM migrations at nuclear waste disposal scale.