Journal Published Online: 21 September 2022
Volume 45, Issue 6

Physical Modeling of Coupled Thermohydraulic Behavior of Compacted MX80 Bentonite during Heating

CODEN: GTJODJ

Abstract

This paper describes a tank-scale test setup and experimental methodology used to investigate coupled heat transfer and water flow processes during heating of compacted MX80 bentonite to high temperatures. Specifically, a temperature of 200°C was maintained by a cylindrical heating element at the center of a compacted bentonite layer containing an array of temperature, dielectric, and relative humidity sensors. In addition to providing an evaluation of the spatiotemporal variations in temperature, relative humidity, degree of saturation, and global volume, the coupled thermohydraulic properties of the bentonite were assessed. A wetting front was initially observed to move away from the central heater, followed by a drying process until reaching thermohydraulic equilibrium. The soil–water retention curve (SWRC) of the bentonite followed a wetting scanning path before following the primary drying path exhibiting a shift in water retention with elevated temperature. Results from the tank-scale test can be used for validation of numerical simulations of drying processes in the engineered barrier system of a high-level radioactive waste geological disposal repository and confirm that a temperature-dependent hysteretic SWRC with scanning paths is required to accurately capture the bentonite response.

Author Information

Lu, Yu
Department of Structural Engineering, University of California San Diego, La Jolla, CA, USA
McCartney, John Scott
Department of Structural Engineering, University of California San Diego, La Jolla, CA, USA
Pages: 19
Price: $25.00
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Details
Stock #: GTJ20220054
ISSN: 0149-6115
DOI: 10.1520/GTJ20220054