The Improvement of Triaxial Apparatus for Thermo-Hydro-Mechanical Behavior of Soils at Elevated Temperatures

The need for thermo-hydro-mechanical studies of soils at high temperatures has increased in environmental geomechanics these years. An important case is the behavior of engineering clay barrier or natural host rock in deep nuclear waste repositories that undergo high temperatures up to 120◦C. Only an apparatus designed for high temperatures can do this kind of studies. This research reviews design, assemble and calibration of a triaxial set that has been made for the first time in Iran. Triaxial tests at high temperatures indicated that sand-bentonite with unit weight in the range of density for engineering barrier of nuclear waste repositories, has contractive behavior. When this mixture was heat up to 110◦C, both peak and critical state shearing strength reduced about 20 percent and critical state friction angle decreased too. These results were similar to other authors’ results that show the apparatus has worked conveniently