Dynamic failure conditions in strong rock masses

It is actually known that dynamic failure takes place in strong rocks given fulfillment of two conditions at the same time—high stress state of rocks and their ability to accumulate sufficient elastic energy of deformation and to release it in failure. Although long-studied, the processes of energy accumulation and liberation in rocks need to be investigated further using the advanced equipment and test facilities. This article presents the experimental research of apatite–nepheline rocks from the Khibiny formation and magnetite–apatite–baddeleyite rocks from the Kovdor deposit in the conditions of three-axial and uniaxial compression. The analysis of the experimental data shows that urite and apatite–nepheline ore (Khibiny) is apt to dynamic failure in both modes of loading, while carbonatite (Kovdor) shows ability to dynamic failure in neither mode. It has also been found that after the transition to three-axial loading and decrease in the contrast properties of the stress tensor components, rock become less capable to dissipate the accumulated energy. In connection with this, the dynamic failure prediction is mostly interested in the modes of loading with the maximum contrast behavior of the stress tensor components in rocks, which is the uniaxial loading. To this effect, the simplified testing procedure is developed and approved, and the criteria are developed for estimating the proneness of rocks dynamic failure by analyzing the pre-limiting deformation curve f rock sample and the elastic strain energy using standard equipment.

Keywords: dynamic failure, strong rocks, elastic strain energy, stress tensor, three-axial compression, uniaxial compression.
For citation:

Kasparyan E. E., Kuznetsov N. N., Shokov A. N., Pak A. K. Dynamic failure conditions in strong rock masses. MIAB. Mining Inf. Anal. Bull. 2020;(4):69-84. [In Russ]. DOI: 10.25018/0236-1493-2020-4-0-69-84.

Acknowledgements:
Issue number: 4
Year: 2020
Page number: 69-84
ISBN: 0236-1493
UDK: 622.02
DOI: 10.25018/0236-1493-2020-4-0-69-84
Article receipt date: 01.03.2019
Date of review receipt: 07.05.2019
Date of the editorial board′s decision on the article′s publishing: 20.03.2020
About authors:

E.E. Kasparyan1, Dr. Sci. (Eng.), Senior Researcher,
N.N. Kuznetsov1, Researcher, e-mail: nikavalon@mail.ru,
A.N. Shokov, Cand. Sci. (Eng.), Senior Researcher, Saint-Petersburg Mining University, 199106, Saint-Petersburg, Russia,
A.K. Pak1, Researcher,
1 Mining Institute, Kola Scientific Centre of Russian Academy of Sciences, 184209, Apatity, Russia.

 

For contacts:

N.N. Kuznetsov, e-mail: nikavalon@mail.ru.

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