MULTIROCK

Coupled multi-scale modelling of mechanical degradation and transport phenomena in damaging multi-phase geomaterials for environmental applications

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 Obiettivo del progetto (Objective)

'The objective of the project is to develop and apply multi-scale modelling techniques for multi-physical processes in multi-phase geomaterials for the identification of evolving macroscopic properties due to their mechanical degradation (rocks, geomaterials). Multi-scale modelling of mechanical damage is the field of expertise of the applicant. The proposed work will focus on fluid transport through porous materials with evolving damage and damage-induced permeability evolution. Geomechanics problems require the use of computational tools to guide engineers in developing solutions, resulting in models that have produced more realistic solutions. However, various issues hinder their use, including the experimental identification of the complex material parameters needed to utilize them. Geomaterials are subjected to various stimuli corresponding to different, yet coupled, physical phenomena, such as mechanical degradation, fluid transport, thermal or chemical effects. This requires identifying behavioural parameters and laws for all these processes as well as their interactions. The expertise in coupled phenomena available at McGill University (Prof. Selvadurai) will be used in conjunction with multi-scale computational modelling tools to examine damage evolution relevant to large scale problems in environmental geomechanics and structural materials. By combining different physical phenomena using tools capable of modelling complex geomechanical problems with environmental impacts, the project will be multidisciplinary.

The long term developments targeted by the project are firmly founded on advances in computational modelling, with long term applications to environmental geosciences issues relevant, for instance, to deep geological storage of nuclear waste, CO2 sequestration, or groundwater-borne reactive pollutant dispersion in the geosphere being of immediate interest. The corresponding developments will allow to feed long term research efforts upon return at ULB'

Introduzione (Teaser)

To more accurately predict how fluids will spread, EU-funded scientists have designed numerical models that simulate their flow at the pore scale.

Descrizione progetto (Article)

Numerical simulations are also required to extrapolate up to several orders of magnitude over areas where phenomena of interest occur. For example, transport of water through membranes for water treatment and solute transport in soils and underground.

Understanding such transport phenomena in industrial and environmental contexts is difficult due to the complexity of the interactions. The MULTIROCK project team developed a multiscale modelling strategy to address the challenge posed by multiple scales.

The void space of porous materials often contains two or three fluid phases: liquids, gases and plastic solids. Porous materials absorb and diffuse fluid through their body, which affects the physical properties of the deformable body. Furthermore, the fluid flow is affected by damage induced by external loading in conjunction with processes such as corrosion. In this light, a versatile computational technique was used to investigate the effect of progressive degradation on permeability. Pore-scale modelling was adapted for various types of materials such as rocks and soils with complex microstructure.

Once the MULTIROCK scientists had developed their software programmes to accurately model the fluid flow at the pore level, their findings were translated to macroscopic behaviour. The results of multi-scale computations reproduced experimental permeabilities and were excellent fits to mechanical dispersion observed in test beds.

The new techniques should bring modelling to a predictive level, where the forecast of a system's response is of practical interest in engineering applications. The MULTIROCK project results are described in a series of five papers published in international peer-reviewed journals.