Investigation of the Strength Characteristics of Various Bentonites under Different Temperature and Saturation Conditions

In the geological disposal of high-level radioactive waste, bentonite is a key buffer material due to its swelling capability and low permeability. To ensure long-term safety, its properties, particularly uniaxial compressive strength, must be evaluated. After waste emplacement, the buffer is exposed to high temperatures from decay heat and potential groundwater intrusion. Understanding the thermal effects on bentonite performance is crucial, yet studies remain limited. This study conducted uniaxial compression tests on various Japanese bentonites with different origins and characteristics, considering temperature and saturation. The results showed that, regardless of bentonite type, compressive strength decreased under thermal effects. These findings contribute to a database and provide a reference for selecting engineered barrier materials in geological disposal.