Subventions et des contributions :

Subvention ou bourse octroyée s'appliquant à plus d'un exercice financier. (2017-2018 à 2022-2023)

Geomaterials underpin the performance of key infrastructures in civil/mining engineering and energy extraction industries. Accurate modelling and predicting the mechanical behaviours of geomaterials are therefore vitally important. As typical granular materials, geomaterials are essentially multiscale and multiphase. Their macroscopic responses are decisively dictated by the underlying interactions among the constituent particles and their microstructures. Meanwhile, the pores of geomaterials are often fully or partially saturated with fluids like water. The coupling between the deformation of the solid matrix and the fluid flow leads to many complex yet intriguing phenomena including shear banding and fracturing. Due to the material nonlinearity and the coupling effects, as well as the lack of a robust numerical tool to account for both multiscale and multiphase characters, it remains a challenging task to accurately model and characterise geomaterials.

The proposal aims at developing a computational framework to capture the both characters for theoretical geomechanics and practical geotechnical applications, with a particular emphasis in tackling the coupling between pore fluid flow and evolving weak/strong discontinuities, which feature a major failure mode (localisation) in geomaterials. Based on the applicant’s previous work on hierarchical multiscale modelling, the current framework pays a revisit to the classical continuum theory at the macroscale with a newly emerging Peridynamics perspective. Meanwhile, at the micro/mesoscale, the material constitutive responses and microstructural evolutions are reproduced by discrete element simulations to obviate the need of phenomenological constitutive assumptions. A fully coupled hydro-mechanical formulation will also be incorporated to account for the effect of pore fluid. Key effective variables and hydraulic properties will be directly inferred from homogenised microstructural attributes.

The multiscale approach is capable in solving both weak/strong discontinuities in ductile/brittle materials (e.g. embankment failure, hydraulic fracturing). The research will offer a robust and integrated framework combining the strength of both continuum and micromechanics-based methods for modelling of geomaterials, as well as general heterogeneous materials like composites. Hence, it will be of broad interests to geotechnical/mechanical engineers and material scientists. By harvesting the capacity of cutting-edge high performance computing technologies, this tool can provide powerful predictions for next-generation design in civil/mining engineering and mitigation of geohazards in Canada and worldwide.