A CRS Oedometer Cell for Unsaturated and Non-Isothermal Tests

Research into the thermo-hydromechanical (THM) behavior of unsaturated soils and the effect of strain rate on their mechanical responses requires the employment of advanced laboratory testing systems and procedures as well as protocols of correcting the measured data in order to account for errors associated with complex test conditions and apparatus calibrations. This article presents the design and calibration of an innovative constant rate of strain oedometer cell for the characterization of the THM behavior of soils under combined non-isothermal and unsaturated conditions. The advanced oedometer cell enables the simultaneous control of temperature, suction, and stress state within the soil specimens. Temperatures of 20°C to 200°C are applied through a tubular heating element placed at the base of the soil specimen. Suction is controlled using the axis-translation technique and measured using both axis translation and two high-capacity tensiometers accommodated on the periphery of the specimen. The performance of the new cell is assessed based on a set of tests performed on clay specimens, and its merits and advantages are discussed in detail.