Experimental study of temperature effects on physical and mechanical characteristics of salt rock

• Published in: Rock mechanics and rock engineering Vol. 39; no. 5; pp. 469 - 482
• Main Authors: LIANG, W. G, XU, S. G, ZHAO, Y. S
• Format: Journal Article
• Language: English
• Published: Wien Springer 01.11.2006; New York, NY Springer Nature B.V
• Subjects: Applied sciences; Axial strain; Biosphere; Buildings. Public works; Compressive strength; Exact sciences and technology; Geotechnics; High temperature; Integrity; Internal friction; Radioactive wastes; Repositories; Rock; Rocks; Salts; Shear strength; Shear tests; Soil mechanics. Rocks mechanics; Thermal energy; Waste disposal; Wastes; Shear test; Salt rock; Rock mechanics; Stress strain relation; Temperature effect; Experimental study; Physical properties; Uniaxial compression; Salt; physical and mechanical characteristics; Mechanical characteristic; Application; Ultrasound
• ISSN: 0723-2632; 1434-453X
• DOI: 10.1007/s00603-005-0067-2

Because of its advantageous physical and mechanical characteristics, salt rock is considered an excellent host rock for nuclear waste disposal. Nuclear wastes in a salt rock repository will continue to emit radiation and thermal energy for decades after placement, resulting in a significant rise of the surrounding salt rock temperature. Consequently, study of the physical and mechanical characteristics of salt rock under different temperature conditions is essential to ensure the integrity of the salt rock repository and the safe isolation of nuclear wastes from the biosphere. Through a series of physical and mechanical tests on thenardite salt rock at different temperatures (ranging from 20°C to 240°C), it is found that the mechanical parameters have different reactions to a changing temperature. Tests show that the ultrasonic velocity of samples decreases with temperature increase and both the uniaxial compressive strength and axial strain increase with temperature, whereas the tangent modulus E^sub t^ goes in an opposite direction. Meanwhile, the plastic strain increases gradually and strain-softening behavior of the samples becomes increasingly evident. In the pre-set angle shear tests, both the cohesion and internal friction angle increase with temperature. Results obtained in direct shear illustrate that both the peak shear strength and the ultimate shear strength increase with temperature. We conclude that the behavior of thenardite salt rock at high temperatures is still advantageous to the integrity of salt rock repository, assuring the safe isolation of nuclear wastes from the biosphere.[PUBLICATION ABSTRACT]