Strength and Deformability of Rocks at Low Temperatures

Malcolm Mellor

Jan 1971 · Corps of Engineers, U.S. Army, Cold Regions Research and Engineering Laboratory

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Strength tests were made on three types of rock, both 'air-dry' and water-saturated, at temperatures from +25 to -195C, and stress/strain tests were made down to -60C. Strength of air-dry specimens increased with decreasing temperature at an average rate of approximately .002/C and quasi-elastic moduli increased at comparable rates. Static fatigue mechanisms in air-dry rock were apparently influenced by temperature-modification of adsorbed water. Strength of water-saturated specimens increased dramatically as pore water froze, and continued to increase down to -120C, where compressive and tensile strengths were greater than room temperature values by factors of 5, 4 and 2 for sandstone, limestone and granite respectively. Compressive stress/strain curves for saturated rocks became steeper after freezing, and initial tangent moduli for saturated high porosity rocks increased by well over an order of magnitude. (Author).