Abstract
The use of high-density bentonite-sand mixtures as buffer and sealing materials at the disposal sites of radioactive waste is expected. Although the bentonite–sand mixtures at disposal sites will be in an unsaturated condition during the construction period, they will gradually become saturated by reflooding in the ground water after the service commencement. In the present paper, a series of fully undrained triaxial tests is performed to make clear the shear properties of a high-density bentonite–sand mixture. In the case of a low degree of saturation, the shear strength is relatively large and volumetric expansion is observed. However, in the case of a high degree of saturation, the shear strength is small and volumetric compression is observed. These results suggest that the mechanical properties of high-density bentonite rapidly change with an increasing degree of saturation.
