CHANGE OF ENERGY CHARACTERISTICS OF LITHOSPHERE ELEMENTS DURING THEIR DEFORMATION

Purpose. The purpose of this study is to establish analytical patterns for predicting changes in stress and energy density spent on the destruction of rocks according to experimental studies. To solve this purpose in the article were set the following scientific problems: 1) analytical description of the dependence of the stress σij on the main deformation εij; 2) establishment of calculation parameters that are included in the analytical patterns; 3) analytical description and study of fracture energy density curves. Methodology. In the course of analytical and experimental researches of full diagrams of deformation of rocks the mathematical model of dependence of the stress on the deformation is developed. Physico-mechanical processes of all characteristic sections of the complete deformation diagram were also analyzed and described. Analysis of the resulting curve showed that the rock mass and elements of the lithosphere are not perfectly elastic or plastic objects. Along with the elastic ones, plastic ones are always present to one degree or another. The integration of the obtained analytical expression σ11 = f(ε11) allowed to establish the volumetric energy density spent on the destruction of the rock sample under the action of external load. The maximum activation energy for the considered rock is 0.67 MJ/m3. A comparison of the experimental and calculated values of the energy dependence u(ε1) shows a coincidence over almost the entire range of deformation changes (ε11 = 0..0.04). Findings. The study of rock samples at hard stress allowed to obtain a complete deformation characteristics of the rock. The curve that surrounds the deformation cycles (1) combines pre-boundary, boundary, extremal modes of deformation and destruction of rocks. Equation (4) allows us to establish that the destruction can occur at different values of energy density U(ε). Originality. An analytical description of the energy diagram of deformation and a complete diagram of stress change in the form of a single dependence, which takes into account the boundary and extremal areas, was developed in the work. In contrast to the method of piecewise linear approximation, this approach corresponds to the physics of the process and reduces errors in calculations. Practical implications. Theoretical and experimental analysis of the obtained energy fracture diagrams and complete stress change diagrams in rocks allows to estimate the bearing capacity of a rock mass or other solid body. This allows you to predict critical values of stresses and external loads to prevent failure in a timely manner.