Coupled Osmotic and Swelling Phenomena within Sodium Bentonites for Pollutants Containment Barriers: Theoretical Aspects and Potential Applications
Event details
| Date | 12.12.2013 |
| Hour | 12:15 › 13:15 |
| Speaker | Prof. Mario Manassero |
| Location |
GC B331
|
| Category | Conferences - Seminars |
Sodium Bentonites are clayey soils characterized by a high specific surface and a permanent negative electric charge on the solid skeleton. Their increasing use as hydraulic and contaminant barriers for landfills and soil remediation applications, including the final disposal of nuclear waste, needs to be supported by adequate theoretical modeling of their mechanical behavior and transport properties, in order to assess the expected performance with particular reference to the long term.
To this end, a theoretical framework has been proposed in order to derive constitutive equations for the coupled chemical-hydraulic-mechanical behavior of sodium bentonites. Their solid phase is assumed to be constituted by montmorillonite lamellae having a slit-like geometry, which can be aggregated to form the so-called tactoids. Chemical equilibrium is assumed to be established between the bulk external electrolyte solutions and the internal pore solution at the macroscopic scale, so that the hydraulic pressure and ion concentrations can be evaluated through the Donnan equations. Water and ion transport is described at the pore scale through the generalized Navier- Stokes equation and the generalized Nernst-Planck equations, respectively. Mechanical behavior is modeled taking into account inter-granular contact stresses and electro-static attraction and repulsion forces.
The proposed theoretical approach has been applied to interpret a series of experimental results from many authors (Malusis and Shackelford, 2002; Malusis et al., 2013; Dominijanni & Manassero, 2011 and Dominijanni et al. 2012 among others) and a number of laboratory tests on natural, pretreated and polymer-modified bentonites carried out at Politecnico di Torino using an osmotic cell specifically designed and setup for this research program.
Bio: Mario Manassero has been professor of Geotechnical Engineering at Politecnico di Torino since 2002. He received his Ph.D. from the same university in the 1987. He is Chairman of Technical Committee (TC) no. 215 "Environmental Geotechnics" of the International Society for Soil Mechanics and Geotechnical Engineering (ISSMGE)(2001-2014). His main research activities are devoted to the geotechnical characterisation of soil deposits using in-situ tests, soil improvement and reinforcement methods, containment systems for landfills and polluted subsoils, the mechanical behaviour of municipal and industrial wastes, the chemo-physical interaction between pore fluids and the solid skeleton, multiphase coupled flows and associated transport phenomena.
To this end, a theoretical framework has been proposed in order to derive constitutive equations for the coupled chemical-hydraulic-mechanical behavior of sodium bentonites. Their solid phase is assumed to be constituted by montmorillonite lamellae having a slit-like geometry, which can be aggregated to form the so-called tactoids. Chemical equilibrium is assumed to be established between the bulk external electrolyte solutions and the internal pore solution at the macroscopic scale, so that the hydraulic pressure and ion concentrations can be evaluated through the Donnan equations. Water and ion transport is described at the pore scale through the generalized Navier- Stokes equation and the generalized Nernst-Planck equations, respectively. Mechanical behavior is modeled taking into account inter-granular contact stresses and electro-static attraction and repulsion forces.
The proposed theoretical approach has been applied to interpret a series of experimental results from many authors (Malusis and Shackelford, 2002; Malusis et al., 2013; Dominijanni & Manassero, 2011 and Dominijanni et al. 2012 among others) and a number of laboratory tests on natural, pretreated and polymer-modified bentonites carried out at Politecnico di Torino using an osmotic cell specifically designed and setup for this research program.
Bio: Mario Manassero has been professor of Geotechnical Engineering at Politecnico di Torino since 2002. He received his Ph.D. from the same university in the 1987. He is Chairman of Technical Committee (TC) no. 215 "Environmental Geotechnics" of the International Society for Soil Mechanics and Geotechnical Engineering (ISSMGE)(2001-2014). His main research activities are devoted to the geotechnical characterisation of soil deposits using in-situ tests, soil improvement and reinforcement methods, containment systems for landfills and polluted subsoils, the mechanical behaviour of municipal and industrial wastes, the chemo-physical interaction between pore fluids and the solid skeleton, multiphase coupled flows and associated transport phenomena.
Practical information
- General public
- Free
Organizer
- Prof. Nikolas Geroliminis & Prof. Katrin Beyer
Contact
- Prof. Lyesse Laloui