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SWELLING CHARACTERISTICS OF BENTONITE BASED BARRIERS FOR DEEP GEOLOGICAL REPOSITORY FOR NUCLEAR WASTES: IMPACT OF UNDERGROUND WATER CHEMISTRY AND TEMPERATURE
Session: Rock Mechanics and Engineering Geology I / Mécanique des roches et ingénierie géologique I
Mamadou Fall, University of Ottawa (Canada)
Asmaa Shehata, University of Ottawa (Canada)
Christian Detellier, University of Ottawa (Canada)
The presence of bentonite-sand in deep geological repositories surrounded by aggressive environments of highly saline underground water, high temperature and under confining stress may cause mineralogical changes for bentonite-based materials and impact their physical and physiochemical properties. This could affect the bentonite performance as an engineered barrier system and the overall safety of the deep geological repositories. The objective of this research is to investigate the impact of Ontario’s underground water salinity and heat generated by the nuclear wastes on the swelling capacity of bentonite-sand engineered barrier materials. Free-swelling and swelling pressure tests have been performed on bentonite-sand mixtures subjected to various chemical (groundwater chemistry) and thermal (heat generated) loading conditions. The obtained results have shown that the groundwater chemistry can significantly deteriorate the swelling properties of the tested bentonite-sand barrier material, whereas the temperature has little effect on the bentonite-sand swelling potential.
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