Seepage and consolidation of bentonite saturated with pure- or salt-water by the method of unified molecular dynamics and homogenization analysis

Bentonite clay is a micro-inhomogeneous material, which consists of clay mi nerals (mainly montmorillonite), macro-grains (mainly quartz), water, air a nd others, Properties of the saturated bentonite clay are essentially chara cterized by the montmorillonite and water (i.e. montmorillonite hydrate), W e analyze the molecular behavior of sodium montmorillonite hydrate Na-1/3, Al-2[Si11/3Al1/3]O-10(OH)(2). nH(2)O by applying a molecular dynamics (MD) simulation method. And by using the MD results we calculate the swelling pr operty of the montmorillonite hydrate, and compare with an experimental res ult. Next, by using the same MD procedure we treat a montmorillonite minera l with a large number of external water molecules to check the properties o f the water, Here we treat pure- and salt-water. Then we calculate the diff usivity and viscosity of water molecules and Na+ and Cl- ions. For extending the microscopic characteristics of constituent materials to a macroscopic seepage behavior of the micro-inhomogeneous material we apply a homogenization analysis (HA), That is, starting with the Navier-Stokes eq uation with distributed viscosity that is calculated by the former MD proce dure we determine macroscopic permeability characteristics of bentonite for both cases of pure- and salt-water. Then, by using the permeability proper ty we calculate long-term consolidation behavior of buffering clay, which i s planed to be used for high-level radioactive waste (HLRW) management. Her e the deformation is treated under the well-defined Cam clay model. (C) 200 1 Elsevier Science B.V. All rights reserved.