PSI - Issue 32

ScienceDirect Available online at www.sciencedirect.com Sci nceD rect StructuralIntegrity Procedia 00 (2021) 000 – 000 Available online at www.sciencedirect.com ScienceDirect StructuralIntegrity Procedia 00 (2021) 000 – 000 Available online at www.sciencedirect.com

www.elsevier.com/locate/procedia www.elsevier.com/locate/procedia

Procedia Structural Integrity 32 (2021) 166–172

© 2021 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the XXIIth Winter School on Continuous Media Mechanics” Abstract A new criterion has been developed for the strength of rocks in the condition of true triaxial stress. The criterion parameters are calculated based on the results of a complex determination of the ultimate strength, which includes uniaxial tensile, uniaxial compression and biaxial compression. The results of the complex determination of strength indicators are presented, as well as of the parameters of the proposed criterion for various rock types. The dependences of siltstone strength on the values of intermediate and minimum principal stresses have been formulated. The results of the comparative analysis are given on the theoretical and experimental data obtained by Karman, Becker and Mogi for various load patterns. © 2021 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license ( https://creativecommons.org/licenses/by-nc-nd/4.0 ) Peer- review under responsibility of the scientific committee of the XXIIth Winter School on Continuous Media Mechanics” Keywords: rock, intermediate principal stress, strength criterion 1. Introduction Rock destruction is a very important phenomenon, which is associated with distribution of cracks under critical loads and makes the elements of underground mining sites lose their bearing capacity. In general, the triaxial stress condition of rocks in a formation is called the true stress and is characterised by three unequal principal stresses, i.e. the maximum ( ͳ ), the minimum ( ͵ ) and the intermediate ( ʹ ) ones. Therefore, one of the main goals in geomechanics is to study the strength properties of rock formations under the true stress. The first studies of the rocks under the triaxial stress were conducted by Karman and Becker on the initiative of Professor Prandtl at the laboratory of the University of Göttingen using Carrara marble samples (Filonen ko-Borodich, 1961). The tests by XXIIth Winter School on Continuous Media Mechanics THE STRENGTH CRITERION FOR ROCKS UNDER TRUE TRIAXIAL STRESS Ivan Pankov* Mining Institute of the Ural Branch of the Russian Academy of Sciences, 78a Sibirskaya St, Perm, Perm Krai 614007, Russian Federation Abstract A new criterion has been developed for the strength of rocks in the condition of true triaxial stress. The criterion parameters are calculated based on th results of a complex determination of t e ultimate strength, which includes uniaxial tensile, uniaxial ompression an biaxial compression. The r sults of the complex d termination of strengt indicators are presented, as well s of the arameters of the pr pos d criterion for various r ck types. The dependenc s of siltstone strength on the values f intermediate and minimum principal stresses have been formulated. The r sults of the comparative analysis are given on the theoretical and experimental data obtained by Karman, Becker and Mogi for various load patterns. © 2021 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license ( https://creativecommons.org/licenses/by-nc-nd/4.0 ) Peer- review under responsibility of t scientific committe of the XXIIth Winter School on Continuous Media Mechanics” Keywords: rock, intermediate principal stress, strength criterion 1. Introduction Rock destruction is a very important phenomenon, which is associated with distribution of cracks under critical loads and makes the elem nts of underground i ing sites lose their bearing capacity. In general, the triaxial stress c n ition of rocks in a formati n is called the true stre s and i c aract rised by three unequal principal stresse , i.e. the maximum ( ͳ ), the in mum ( ͵ ) and th interme iate ( ʹ ) ones. Therefore, one of the main goals in geo echanics is to study the strength properties of rock formations und r the t ue stress. The first studies of the rocks under the triaxial stress w re conduct d by Karman and Becker on the initiative of Professor Prandtl at laboratory of the Univer ity of Göttingen using Carrara marble samples (Filonen ko-Bor dich, 1961). The ests by XXIIth Winter School on Continuous Media Mechanics THE STRENGTH CRITERION FOR ROCKS UNDER TRUE TRIAXIAL STRESS Ivan Pankov* Mining Institute of the Ural Branch of the Russian Academy of Sciences, 78a Sibirskaya St, Perm, Perm Krai 614007, Russian Federation

* Corresponding author. Tel.: +7-908-250-4314 E-mail address: ivpan@mi-perm.ru * Corresponding author. Tel.: +7-908-250-4314 E-mail address: ivpan@mi-perm.ru

2452-3216 © 2021 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license ( https://creativecommons.org/licenses/by-nc-nd/4.0 ) Peer-review under responsibility of the sc ientific committee of the XXIIth Winter School on Continuous Media Mechanics” 2452-3216 © 2021 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license ( https://creativecommons.org/licenses/by-nc-nd/4.0 ) Peer-review under responsibility of the sc ientific committee of the XXIIth Winter School on Continuous Media Mechanics”

2452-3216 © 2021 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the XXIIth Winter School on Continuous Media Mechanics” 10.1016/j.prostr.2021.09.024