ABSTRACT:

H2O intercalation results in structure parameter variations and mechanical properties of clay minerals. It matters a great deal in the well-bore stability and inhibiting the hydration swelling of clay minerals. In this present work, the mechanical behavior of Na-montmorillonite (Na-MMT) exposure to a constant pressure 0.025 GPa and variable temperatures (25, 75, 125, 175, 225, 275, 325, 375, 425, 450 ?) in an isobaric isothermal ensemble are investigated using combinations of Monte Carlo and Molecular Dynamic methods. Water model and force field used in the clay-water system are SPC/E model and clayFF, respectively. The results show that after altering the temperature of Na-MMT system, the mobility of the inter-layer species increases, and the hydration shell of the interlayer cations decreases with the rising temperature. The increasing temperature and hydration degree play an important role in the mechanical properties of Na-MMT. After analyzing the effect of temperature on Na-MMT, the results reveal that the bulk modulus, the elastic modulus, and the shear modulus of super-cell present a descending trend and the Poisson ratio shows an ascendant trend as temperature goes up. It is expected the results obtained from this study would help to understand the swelling mechanism of Na-MMT at extremely high temperature.

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