The influence of the weight percentage of the fine and coarse fractions on the excavability index of broken frozen rock mass

The shearing strength tests were carried out on structurally dislocated rock samples to simulate various conditions of broken rock mass in the severe climate of the North. It is shown that strength of the samples grows with the decreasing weight percentage of inclusions and with the increasing compressive loading. The internal friction angle and cohesion change depending on the weight percentage of the fine and coarse fractions. With regard to the found relations, at the preset temperature and moisture content of rocks, the influence of the weight percentage of inclusions in the binder on the excavability index is determined. It is found to be incorrect to use the excavability index found from the traditional formula for rock fracture since broken rocks regelate and, with increasing depth of broken-rock disintegration by blasting, acquire strength comparable with uniform rock mass. The values of the excavability index calculated from the formulas for uniform and fractured rock mass differ by 2 times, which distorts realistic understanding of rock strength at the depth of broken-rock disintegration by blasting. The research findings are the framework for the adjustment of the current concept of the excavability index of broken rocks in mining in the permafrost zone.

Alkova E. L., Panishev S. V., Maksimov M. S. The influence of the weight percentage of the fine and coarse fractions on the excavability index of broken frozen rock mass. MIAB. Mining Inf. Anal. Bull. 2021;(12–1):29—38. [In Russ]. DOI: 10.25018/0236_1493_2021_121_0_29.

Alkova E. L.¹, Cand. Sci. (Eng.), Researcher of the Laboratory, nelealc12@rambler.ru;
Panishev S. V.¹, Cand. Sci. (Eng.), Leading researcher of the Laboratory, bsdpsv@mail.ru;
Maksimov M. S.¹, Junior researcher of the Laboratory, mexes_07@mail.ru;
¹ N. V. Chersky Mining Institute of the North, Siberian Branch of Russian Academy of Sciences, Yakutsk, Republic of Sakha (Yakutia), Russia.

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