Far Eastern Federal University, Vladivostok, Russia:

B. G. Tarasov, Professor, Doctor of Engineering Sciences, bgtaras@gmail.com

The research has found that the fan mechanism can create shear fractures in strong rocks under low shearing stress. Obviously, the strength properties of such rocks can inconsistently be estimated as both strong and weak. The fact is that these rocks are able to sustain high stresses but only till the origination of an incipient fan structure; then, rocks become extremely weak in relation to shear fracturing. This article offers a detailed analysis of the specified inconsistency and illustrates the specificity of the fan structure formation on laboratory samples and in full-scale conditions. A new explanation is given for a variety of representative features of earthquakes initiated by dynamic shear fractures. The connection between the latter and deep-level rock bursts in mines is tracked.
The study was supported by the Ministry of Science and Higher Education of the Russian Federation, Grant No. RFMEFI58418X0034.

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