ABSTRACT
Elastic properties of host rocks of Yakutia’s diamond deposits were studied using STO 05282612–001–2013 internal standard. The standard was developed based on an original procedure that enables determination of static elastic properties (modulus of elasticity, Poisson’s ratio) under variation of temperature and water content in a specimen, which is neglected by the effective Russian and international standards but is of critical importance in mine construction in permafrost zone. The testing includes multiple loading of a specimen within the range of low reversible strains, which enables highly accurate measurement of strain and physically correct estimation of temperature effect on change in properties of the material passing from thawed to frozen state. Air-dry and wet specimens of the rocks (limestone, siltstone) were tested under uniaxial compression. Specimen with extensometers attached to it was placed in a temperature control chamber and tested sequentially under room temperature and, then, under 0°C, −20°C, and −40°C. It was found that as the temperature is lowered, the elasticity modulus of the specimen grows and Poisson’s ratio remains unaltered. To study the effect of moisture, a specimen was placed in water until complete saturation. The tests were carried out in the course of natural drying of the specimen at certain time intervals, and the values of the elastic modulus and Poisson’s ratio were evaluated based on the resultant stress-strain diagrams. It was observed that the change in elastic properties as a function of water saturation has significantly nonlinear character.
