Bentonite THM behaviour at high temperatures: experimental and numerical analysis

摘要

The Temperature Buffer Test is a heated full-scale field experiment carried out at the Aspo Hard Rock Laboratory in Sweden, simulating repository conditions for radioactive waste. The initial thermo-hydro-mechanical (THM) evolution in the clay barrier was investigated in a separate mock-up test. The paper describes this laboratory experiment and the corresponding numerical simulations. Most of the related work refers to THM analyses of bentonite barriers well below 100℃, but here higher temperatures are considered. A 20 cm closed specimen of compacted MX-80 bentonite was subjected to a temperature gradient (84℃ and 120℃ at the end points). The evolution of temperature, relative humidity, pore pressure and stresses was monitored at several points. The test was allowed to reach steady-state conditions. The specimen was then sampled and analysed in terms of water content and bulk density.