Науковий вісник НГУ

The improvement of method of computation of the contact normal tensions distribution at compression of rock samples

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Category: Geotechnical and mining mechanical engineering, machine building

Last Updated on 28 July 2014

Published on 13 August 2013

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Authors:

L.M. Vasilyev Doc. Sci. (Tech.), Professor, N.S. Polyakov Institute of Geotechnical Mechanics of National Academy of Sciences of Ukraine, Dnipropetrovsk, Ukraine

D.L. Vasilyev, Cand. Sci. (Tech.), N.S. Polyakov Institute of Geotechnical Mechanics of National Academy of Sciences of Ukraine, Research Fellow, Dnipropetrovsk, Ukraine

K.V. Tsepkov , N.S. Polyakov Institute of Geotechnical Mechanics of National Academy of Sciences of Ukraine, Research Fellow, Dnipropetrovsk, Ukraine

O.O. Potapenko, N.S. Polyakov Institute of Geotechnical Mechanics of National Academy of Sciences of Ukraine, Postgraduate Student, Dnipropetrovsk, Ukraine

Abstract:

Purpose. The main parameter – a constant characterizing the mechanical properties of rocks – is the resistance of their sample to uniaxial compression. This parameter is defined – ultimate strength – on the special presses, which are available in specialized institutions. However, the companies need operative calculated method for measuring parameter of the rocks strength. The starting point of development of this method is the knowledge of the distribution regularity of contact tensions. Therefore the purpose of this work is the scientific ground for the choice of distribution regularity of contact tensions, providing the analytical determination of the rock samples strength, adequately corresponding to the experimental data.

Methods. The most reasonable method of calculation of contact tensions is the method of L. Prandtl, used in processing metal by pressure. In contrast to metals, rocks have an internal friction, which requires improvement of this method. Therefore, this work contains the analysis of different methods of calculation of contact tensions, based on definition of a balance between the derivatives of normal horizontal and vertical tensions, by the special solution of two differential and one algebraic equations.

Findings. The formulas for calculation regularities of normal and tangent tensions distribution on the contact surface of the rock samples are obtained.

Originality. The methods for calculation regularities of the contact tensions distribution received their further development, and at is given the estimation of their reliability by comparing the calculated ultimate strengths of the rock samples with the reference data.

Practical value. The recommended methods, using technique of the theory of slip lines, allow to determine the ultimate strength and to develop a method of charting “tension-longitudinal strain” without using expensive pressing equipment. The practical value lies in using of three metrics of rocks (resistance to shear, rates of contact and the internal friction of rocks) that are simply can be estimated by experiment directly in enterprises and promptly used by them in calculations of the ultimate strength.

References:

1. О правомочности применения закона о линейной связи между контактными напряжениями для расчёта предела прочности горных пород / Л.М. Васильев, К.В. Цепков, А.В. Пазынич [и др.] // Науковий вісник НГУ. – 2008. – № 3. – С. 3–6

Vasilyev, L.M., Tsepkov, K.V., Pazynich, A.V. [et al.], (2008), “On the eligibility of application the law of the linear relationship between the contact tensions for calculation the limit of strength of the rock”, Naukovyi visnyk NGU, no. 3, p. 3–6

2. Васильев Д.Л. Определение влияния внутреннего и внешнего трения горных пород на их прочность при одноосном сжатии: автореф. дис. на соискание научн. степени канд. техн. наук: 05.15.09 / Д.Л. Васильев. – Днепропетровск, 2002. – 25 с.

Vasilyev, D.L. (2002), “Determining the influence of internal and external friction of rocks on their strength in uniaxial compression” Abstract of Ph.D. dissertation (Cand. Sci. (Tech.), Geotechnical and mining mechanics, 05.15.09, Dnipopetrovsk.

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