The Compressive Strength of Permafrost and Ice in Their Natural States

Abstract

Laboratory and field tests of disturbed and undisturbed specimens of permafrost and active layer were conducted with the objective of determining the compressive strengths of the specimens at various temperatures, 1oading rates, and moisture contents. The specimens comprised several varieties of the following types of ground: coarse-textured, sand, silt, loam, peat, and ice. The test specimens were cubes and nearly cubical prisms ranging in size from 2 to 10 cm on a side. The test temperatures ranged from +4 to -7° C, and the loading, rates ranged from 1 kg per sq cm per min to instantaneous rupture 1oad. The moisture content ranged from relatively low to considerable supersaturation. It was found that the compressive strength invariably increased with decreasing temperature. The effect of loading rate varied with each type of ground. Increase in moisture content up to saturation usually resulted in relatively higher strength, the actual variation depending on the particular. type of ground. The specific results are compiled in Table XXXII in the text.