Hydro-mechanical behaviour of high-density bentonite pellet on partial hydration

Abstract : The hydro-mechanical behaviour of a high-density bentonite pellet, potential candidate for engineered barriers in high-level radioactive waste disposal, is investigated through laboratory tests. Water content and volumetric strain are first determined at various suctions (ranging from 9 to 89 MPa) during partial hydration from its initial state. Afterwards, compression tests allow Young's modulus and strength to be determined at various suctions. The experimental results are then interpreted by using an existing model describing the hydro-mechanical behaviour of an aggregate in compacted expansive clay. The analyses show that a single set of parameters is sufficient to predict the suction dependency of volumetric strain, Young's modulus and compressive strengths. These findings would be helpful for further numerical investigations on the hydro-mechanical behaviour of granular bentonite-based engineered barriers by using both finite- and discrete-element methods.