A double-structure hydromechanical constitutive model for compacted bentonite

Model for predicting evolution of microstructural void ratio in compacted clayey soils

“…Several additional factors contribute to changes in the soil microstructure, which include the aging effect (e.g., Delage et al 2006), low or high temperature (e.g., Xu et al 2018;Villar et al 2019), pore-water chemistry (e.g., Pedrotti 2016), andcementation (e.g., Di Sante et al 2014); however, these factors are not discussed because it is beyond the scope of the present study. During the past decade, remarkable advancements have been achieved in modelling the behavior of compacted clayey soils incorporating explicitly the microstructural evolution, such as the soil water characteristic curve (SWCC) (e.g., Romero et al 2011;Hu et al 2013;Della Vecchia et al 2015), hydraulic conductivity (e.g., Romero 2013;Wang et al 2013;Azizi et al 2020), mechanical constitutive behavior (e.g., Gens et al 2010;Alonso et al 2013;Qiao et al 2019), and shear strength and tensile strength properties (e.g., Alonso et al 2010;Trabelsi et al 2018).…”

“…Most studies on the microstructure of compacted clayey soils are related to the double-porosity aggregated structure, which is a typical structural characteristic at the dry-of-optimum compaction state. The microstructural void ratio is strongly associated with the microstructural state, which 4 influences the hydromechanical behavior of compacted soils (e.g., Alonso et al 2013;Mašín 2013;Qiao et al 2019;Cheng et al 2020). The identification of different populations of soil pores (i.e.…”

A New Double-Porosity Macroscopic Model of Bentonite Free Swelling

“…Therefore, it is advisable to use conceptual models that are based on at least a double-porosity approach, the simplest of multiporosity conceptualizations, as a macroscopic basis for simulation. The works of authors such as Moyne and Murad (2003), Mainka et al (2014), Qiao et al (2019) andSchreyer Bennethum et al (1997) provide a robust conceptual foundation for the development of double-porosity models. The conceptual framework that defines the Barcelona Expansive Model (BExM; Alonso et al, 1999), which has been applied with satisfactory results by various authors (Sánchez et al, 2005(Sánchez et al, , 2016Guimarães et al, 2013;Navarro et al, 2017Navarro et al, , 2019 for instance), is adopted in this study.…”

Numerical model of free swelling processes in compacted MX-80 bentonites

“…To take into account this structure in a macroscopic model of the system, a double porosity approach can be adopted to model the thermo-hydro-chemo-mechanical behaviour of compacted clays. [5][6][7][8][9][10] Each structural level is assigned a different continuous medium, while both media occupy the same spatial domain. 11 The coupled increase of total strain d (vectors are identified in bold, and the engineering or Voigt notation is used for the stress and strain tensors) can be computed using an additive approach (see Sánchez et al 12,13 , for example), Fig.…”

“…It is not easy to find formulations in the literature to introduce such a destructuration process in the numerical models used to simulate the behaviour of bentonite clay barriers. Therefore, the formulation proposed by Qiao et al 10 to introduce the split of clay particles in a double structure hydromechanical constitutive model is of interest.…”