Rock structure and scale effect
- G.V. Plekhanov Saint Petersburg Mining University
Abstract
Under conditions of uniaxial compression at strain rate variation from 10 +2 to 10 -8 s -1, samples of natural rock salt were investigated for strength. For the first time, a 40% drop in strength in the range of high speeds and a decrease in the work of fracture by tens of times were found, which contradicts the kinetic concepts. Experiments carried out on salt samples artificially produced by pressing at a pressure of 700 MPa showed good agreement with kinetic representations. The difference in the properties of natural salt and artificially prepared samples is explained by the difference in their structure: natural salt is characterized by a large scattering of structural crystallite sizes.