Numerical and Experimental Investigation of Bentonite-Sand Mixtures

ABSTRACT: Deep geological repository (DGR) is the most preferred option for the long-term disposal of low, intermediate, and high-level radioactive wastes in many countries. DGR safety depends mainly on the multiple-barrier system of both natural and engineered barriers. Bentonite-based materials have been suggested as one of the effective engineering barriers in DGR, due to their low permeability, high swelling pressure, and retention of radionuclides. Swelling characteristics of bentonite-based materials is a crucial factor in assessing its long-term performance, hence the safety of DGR. Numerous laboratory tests have been conducted to determine the swelling properties of bentonite-based sealing materials. In this study, laboratory tests on swelling properties are performed using different standard methods such as the free swelling and constant volume methods. Additionally, numerically simulated swelling tests are conducted to predict swelling characteristics of bentonite-based material and compared with the experimental results.