Thermal influences on swelling-pressure and swelling-deformation of bentonites and its factors

In geological disposal of high-level radioactive wastes, bentonite based buffer fills up the space between waste-container and bedrock, because it has a swelling property and low permeability. High level radioactive wastes generate decay-heat, and it is apprehended that the swelling characteristics of bentonite declines by the decay-heat of wastes. To contribute to this problem, this study investigated swelling-pressure and swelling-deformation of bentonites experienced some thermal histories in the laboratory. Moreover, this study discusses mechanism of thermal influences to bentonite-swelling by considering the above experimental results with chemical analyses about heated bentonites. (author)