Vasyliev L., Vasyliev D., Krasovskyi I., Rizo Z., Kress D. Mathematical model of the failure of tall prismatic rock samples with a high internal friction angle

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Parent Category: Geo-Technical Mechanics, 2024
Category: Geo-Technical Mechanics, 2024, Issue 170

Geoteh. meh. 2024, 170, 55-64

 

MATHEMATICAL MODEL OF THE FAILURE OF TALL PRISMATIC ROCK SAMPLES WITH A HIGH INTERNAL FRICTION ANGLE

Vasyliev L.  Vasyliev D. Krasovskyi I.  Rizo Z. Kress D. 

M.S. Poliakov Institute of Geotechnical Mechanics of the National Academy of Sciences of Ukraine

UDC  [622.02:539.2/.8]:622.831.325

Language: English

Abstract. The mechanical properties of rocks are among the most critical factors determining their resistance to failure, particularly significant in the context of the mining industry and underground operations. Traditionally, such tests have been regulated by state standards (GOSTs) involving the crushing of samples with regular geometries, such as cubes, prisms, and cylinders. The primary objective of these standards is to determine the compressive strength limit, a key indicator for assessing material stability under load.

Tests are conducted on specimens with heights slightly exceeding their cross-sectional dimensions, enabling a more accurate simulation of rock behavior under real geological conditions. A major parameter for analyzing the stress-strain state of rocks is the strength limit and residual strength, evaluated through "stress-strain" diagrams obtained during sample failure.

Such characteristics are typically determined using specialized presses available in major research centers like the Institute of Geotechnical Mechanics of the National Academy of Sciences of Ukraine and the Kryvyi Rih National Technical University. However, this equipment demands skilled personnel, regular maintenance, and is often distant from mining sites, creating challenges in obtaining timely information about rock strength - an essential factor for mining safety.

This article introduces a new analytical method for calculating the strength and residual strength of rocks, based on more accessible and straightforward tests. This method facilitates the determination of four key parameters: shear strength limit, coefficients of internal and contact friction, and the material’s elastic modulus.

The proposed approach not only simplifies the evaluation of strength characteristics but also provides a more accurate description of failure processes in taller samples, which is crucial for engineering calculations and the design of mining structures. Research findings indicate that increasing the sample height significantly reduces its strength; for instance, doubling the height can decrease the ultimate strength by up to 30%.

Consequently, the proposed analytical method enhances the ability to obtain rock strength data directly in the field, enabling swift stability assessments and reducing the risk of accidents. This contributes to improving efficiency and safety in mining operations through more precise predictions of rock behavior under load. The method is valuable for both research and practical applications, offering engineers and designers a tool for more detailed analysis of rock strength characteristics.

Keywords: rock, strength limit, failure, crack, stress-strain diagram.

 

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About the authors:

Vasilyev Leonid, Doctor of Technical Sciences (D.Sc.), Professor, Senior Researcher in Department of Pressure Dynamics Control in Rocks, M.S. Poliakov Institute of Geotechnical Mechanics of the National Academy of Sciences of Ukraine (IGTM of the NAS of Ukraine), Dnipro, Ukraine, This email address is being protected from spambots. You need JavaScript enabled to view it.  ORCID 0000-0002-8146-0812

VasylievDmytro,Doctor of Technical Sciences (D.Sc.), Senior Researcher, Senior Researcher in Department of Elastomeric Component Mechanics in Mining Machines, M.S. Poliakov Institute of Geotechnical Mechanics of the National Academy of Sciences of Ukraine (IGTM of the NAS of Ukraine), Dnipro, Ukraine, vasyliev.d.l@dsau,dp.ua ORCID 0000-0001-6864-357X

Krasovskyi Ihor, Candidate of Technical Sciences (Ph.D)., Researcher, Department of Rock Mechanics, M.S. Poliakov Institute of Geotechnical Mechanics of the National Academy of Sciences of Ukraine (IGTM, NASU), Dnipro, Ukraine,
This email address is being protected from spambots. You need JavaScript enabled to view it. ORCID 0000-0002-4122-4292

RizoZakhar,Ph.D. Student, Department of Elastomeric Component Mechanics in Mining Machines, M.S. Poliakov Institute of Geotechnical Mechanics of the National Academy of Sciences of Ukraine (IGTM of the NAS of Ukraine), Dnipro, Ukraine,
This email address is being protected from spambots. You need JavaScript enabled to view it.  ORCID 0000-0002-8271-7886

Kress Denys,Ph.D. Student, Department of Elastomeric Component Mechanics in Mining Machines, M.S. Poliakov Institute of Geotechnical Mechanics of the National Academy of Sciences of Ukraine (IGTM of the NAS of Ukraine), Dnipro, Ukraine,
This email address is being protected from spambots. You need JavaScript enabled to view it. ORCID 0009-0001-9504-5695