4_2020_sen_12

Title of the article

DEVELOPMENT OF CALCULATION METHOD FOR TENSILE STRENGTH OF ROCK SAMPLES UNDER COMPRESSION
Authors

VASIL’EV Leonid M., D. Sc. in Eng., Prof., Head of the Department of Rock Destruction Issues, Institute of Geotechnical Mechanics named by N. Poljakov of National Academy of Sciences of Ukraine, Dnipro, Ukraine, This email address is being protected from spambots. You need JavaScript enabled to view it.">This email address is being protected from spambots. You need JavaScript enabled to view it.

ZHURAVKOV Michael A., D. Sc. in Phys. and Math., Prof., Head of the Department of Theoretical and Applied Mechanics, Belarussian State University, Minsk, Republic of Belarus, This email address is being protected from spambots. You need JavaScript enabled to view it.">This email address is being protected from spambots. You need JavaScript enabled to view it.

VASIL’EV Dmitriy L., D. Sc. in Eng., Senior Researcher, Institute of Geotechnical Mechanics named by N. Poljakov of National Academy of Sciences of Ukraine, Dnipro, Ukraine, This email address is being protected from spambots. You need JavaScript enabled to view it.">This email address is being protected from spambots. You need JavaScript enabled to view it.

MALICH Mykola G., Ph. D. in Eng., Assoc. Prof., Associate Professor of the Department of Metallurgical Production Machines and Units, National Metallurgical Academy of Ukraine, Dnipro, Ukraine, This email address is being protected from spambots. You need JavaScript enabled to view it.">This email address is being protected from spambots. You need JavaScript enabled to view it.

NAZAROV Oleksandr E., Second Category Engineer, Institute of Geotechnical Mechanics named by N. Poljakov of National Academy of Sciences of Ukraine, Dnipro, Ukraine, This email address is being protected from spambots. You need JavaScript enabled to view it.">This email address is being protected from spambots. You need JavaScript enabled to view it.
In the section GEOMECHANICS
Year 2020 Issue 4 Pages 85–91
Type of article RAR Index UDK 622.028:620.173.24; 539.3 Index BBK  
DOI https://doi.org/10.46864/1995-0470-2020-4-53-85-91
Abstract The paper describes a procedure for improving the approach to determining the ultimate strength of rock samples, the basic method is L. Prandtl’s method. In earlier works of the authors of this paper, the L. Prandtl’s method was improved in relation to rocks, using a general algebraic equation for calculating horizontal normal stresses depending on the vertical component and mechanical characteristics of the rock. Here, the authors reject the assumption that the tangent contact stresses resulting from L. Prandtl's solution do not depend on the abscissa x and on the variable vertical stresses, in contrast to the well-known Coulomb–Amonton law, according to which the tangent stresses are directly proportional to the vertical pressure. The regularities of contact normal and tangential stresses distribution at failure of prismatic samples are clarified. As result, the method was developed for calculating the tensile strength of samples with three characteristic values of mechanical properties: kп, yield strength of material in shear; ρ, angle of internal friction; fс, coefficient of contact friction. These characteristics can be established experimentally by simple experimental studies. The proposed approach is effective for constructing ultimate curves and diagrams of “stress — longitudinal strain” of rocks in the case of contact friction. A comparative evaluation is given for the proposed method for calculating the tensile strength of samples during their destruction with experimental data. Comparison of the calculated tensile strength with experimental data shows that the relative error of calculations according to the proposed method is significantly lower than the relative error of calculations performed using the E. Unksov’s method. The proposed method can be recommended for practical application.
Keywords

rock, tensile strength, contact friction, contact stresses, fracture
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