TY - GEN A1 - Grandas Tavera, Carlos Eduardo A1 - Wichtmann, Torsten A1 - Machaček, Jan A1 - Nitsch, Antonia ED - Zdravkovic, Lidija ED - Kontoe, Stavroula ED - Tsiampousi, Aikaterini ED - Taborda, David T1 - An extended theory of porous media for expansive soils T2 - 10th European Conference on Numerical Methods in Geotechnical Engineering (NUMGE2023) N2 - The successful simulation of the behaviour of expansive soils using FEM strongly depends on the acting hydromechanical processes and their proper consideration. During swelling processes, part of the pore water is bound to the solid. However, the associated change of volume fractions in the porous medium and its contribution to the overall material behaviour is not accounted for in most numerical frameworks. A numerical framework based on the theory of porous media and a novel constitutive model is proposed. The theory of porous media includes a distinct swelling water phase that does not participate in the flow through the pore space. A bidirectional mass transport enables the transition from free to swelling water during change in water content. The reduction of the effective pore space is considered at the finite element level. By consistent balancing in the governing equations, the swelling induced reduction of hydraulic conductivity is directly accounted for. The performance of the proposed framework is demonstrated by back calculation of laboratory tests on different materials. Its capabilities to simulate complex loading paths in (un)saturated conditions with a single set of parameters are shown. KW - Swelling; Expansive soils; Partial saturation; Hydro-mechanical coupling; Porous Media Y1 - 2023 U6 - https://doi.org/10.53243/NUMGE2023-379 ER - TY - GEN A1 - Nitsch, Antonia A1 - Leuthold, Jan A1 - Machaček, Jan A1 - Wichtmann, Torsten A1 - Grandas Tavera, Carlos Eduardo T1 - Experimental investigations of the stress-dependent swelling behavior of reconstituted claystone T2 - Fachsektionstage Geotechnik 2021: 24. Symposium Felsmechanik und Tunnelbau N2 - An experimental campaign giving a holistic overview on the hydro-mechanically coupled behavior of Opalinus Clay shale is presented. Oedometric swelling tests show a pronounced stress pathdependent swelling behavior that is governed by the local permeability and the mechanical preloading stress. A linear coupling between deformation and volumetric water content can be established during initial saturation that causes a swelling-induced reduction of the hydraulic permeability. Swelling deformation and pressure result in the mechanical degradation of the material with a reduction of preloading stress and elastic stiffness. Based on the experimental results, fundamental characteristics of the material behavior are derived and form the basis for the future development of a new constitutive model that is able to predict the hydro-mechanically coupled material response Y1 - 2021 UR - https://www.researchgate.net/profile/Antonia-Nitsch/publication/353039348_Experimental_investigations_of_the_stress-dependent_swelling_behavior_of_reconstituted_claystone/links/60e583454585156c95e89477/Experimental-investigations-of-the-stress-dependent-swelling-behavior-of-reconstituted-claystone.pdf ER -