Influence of Unloading Conditions on the Rock Mass Strength of the Overall Slope of the Open Pit

The study described in this paper provides a method for accounting the effect of unloading condition on the strength of a rock massif. This was done by estimating the lower limits of crack initiation and the upper limits of interaction for the in-situ rock massif under unloading conditions. The results show that the mechanism of extension crack propagation is a function of low confinement conditions which, in their turn, leads to a decrease in the strength of the rock massif, depending on the maximum component of the redistributed stress field. Under low confinement and weak rock conditions, the mechanism of progressive failure consists of propagation of failure along a pre-existing geologic discontinuity and the propagation of extension cracks through the rock bridges. The study focused particularly on the in-situ strength of the rock massif and the predicted location of the global failure surface under low-confinement conditions. The article presents implications for a better understanding of rock mass behavior and a more satisfactory method of slope stability analysis that can simulate a brittle in-situ rock mass strength. An example of a real slope will be used to illustrate and evaluate stability based on the application of the in-situ rock mass strength criterion discussed in this paper. When applying the traditional rock failure criteria, which does not take into account the extension cracks in the rock massif, the strength of the rock massif will be overestimated, and hence the stability of the exposed mining slopes.

Hovakimyan V. V., Manukyan L. A. Influence of Unloading Conditions on the Rock Mass Strength of the Overall Slope of the Open Pit. MIAB. Mining Inf. Anal. Bull. 2022;(9−1):14—24. [In Russ]. DOI: 10.25018/0236_1493_2022_101_0_14.

Hovakimyan V. V.¹, Researcher (Post Graduate Student), Geotechnical Engineer of ‘LMI’ CJSC, e-mail: vrezh_hovakimyan@mmi.am, ORCID ID: 0000-0002-0954-216X,
Manukyan L. A.¹, Dr. Sci. (Eng.), Assoc. Professor, e-mail: manukyanlevon-a@rambler.ru;
¹ National Polytechnic University of Armenia (NPUA), Institute of Mining, Metallurgy and Chemical Technologies, Yerevan, Armenia.

Hovakimyan V. V., e-mail: hovakimyanvrej95@mail.ru

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