Parallel Session C-6: Material behaviour - Chair: Martin Lesueur

- A phase field discrete element method is developed to model the irregular shape and its heterogeneous evolution of granular materials. - This model has allowed us to investigate the phenomena of pressure-solution and dissolution at the grain scale level.

• Particle-based methods are explored in modelling laboratory-scale granular bentonite samples of interest to engineered barrier system design. • The discrete element method is applied to study the effect of pellet shape on the deformation of dry pellet packings and pellet-powder mixtures under oedometer compression. • The new XMm method allows discretising heterogeneous pellet-powder mixtures into sets of continuum units where flow upon hydration is simulated at the different pore levels.

Cyclic loading is crucial for the design under lateral loading of monopile foundations of offshore wind turbines. Finite element analysis of the monopile under cyclic loading is necessary. However current advanced constitutive models fail to capture adequately cyclic loading of sand. Results of HySand, a new multisurface model developed in the hyperplastic framework, will be compared to data by Wichtmann on Karlsruhe fine sand. The focus will be on complex triaxial tests, including cyclic stress and strain-controlled undrained tests.

Modelling the constitutive relations of chemically corroded carbonate rocks is essential for the design and stability evaluation of engineering constructions in karst areas. This study presents a sequentially coupled chemical mechanical damage constitutive model for carbonate rock, based on the Arrhenius theory, Lemaitre's strain equivalent principle and the statistical approach. A modified Mohr-Coulomb criterion with mobilized friction angle and cohesion is introduced to capture the nonlinear relationship between the compressive strength and confining stresses. Finally, the proposed model is validated and shows agreement with experimental data. Keywords: Damage model; Chemical mechanical coupled condition; Modified Mohr-Coulomb criterion

Nonlinear effective stress site response analyses are commonly used to estimate dynamic soil behaviour, seismic wave propagation through the soil medium, and resulting ground motions. These analyses can be used to identify potential hazards (e.g., landslides, settlements, liquefaction) and to estimate dynamic loads on superstructures in areas that are prone to natural or induced earthquakes, which can help with disaster planning and risk mitigation efforts. In this study, the influence of fabric anisotropy, which is induced during the soil formation process, on the response of sand deposits has been assessed through one dimensional site response and response spectrum analyses.