Comparison of Mechanical Properties of Dry, Saturated and Frozen Porous Rocks

Abstract

The mechanical properties of frozen rocks are very different from the properties of the same lithologies under ambient temperature. The goal of this paper is to describe the changes in the physical parameters of rocks caused by freezing. In addition, estimations are given on how these parameters are influenced by the intrinsic properties of rocks. For the tests, cylindrical specimens were made from highly porous Miocene limestone and porous rhyolite tuff. The samples were tested in air dry, water saturated, and frozen (−20 °C) conditions. Besides the porous stones, ice specimens were also made and used for the same tests. The laboratory tests included the determination of density, ultrasound speed propagation, porosity, capillary water absorption and strength parameters. The test results obtained under the three conditions were compared. The data set of measured physical parameters was analyzed by using regression analyses. Correlations were calculated for the measured physical parameters of air-dry, saturated, and frozen conditions. The results suggest that a stronger correlation exists between the strength and density of frozen specimens than between the strength and density of air-dry specimens. Equations were also found that describe the relationships between the density and uniaxial strength of ice and various porous rocks.