PROCEEDINGS OF THE RUSSIAN HIGHER SCHOOL
ACADEMY OF SCIENCES

Abstract
The tendency of rocks to brittle fracture was evaluated through experimental studies and reference analysis conducted by the authors. The experimental procedure included the installation of the samples between the press "Instron-1" plates and their uniaxial loading to failure. In doing this, the value of the load, signals of electromagnetic radiation and the current arising in the sample as a result of the occurrence of electrical charges on the sides of a moving crack were recorded .During the experiments, more than 70 samples of rocks were investigated, among them – granite, limestone, marble, sandstone, quartz syenite, tuff, marbled limestone, garnet - epidote skarn, sye nite, etc., which were made in the form of a rectangular and a cylinder with the height from 0,06 to 0,17 m and with a transverse dimension of 0,03–0,06 m. When studying the process of destruction of rocks in the laboratory, we estimated the values of the electromagnetic energy emitted by the crack. It was found that the highest level of electromagnetic energy corresponds to the destruction of fragile rocks (quartzite , quartz syenite ), and the lowest energy corresponds to plastic rocks (marbled limestone). The level of the surface energy density of the electromagnetic radiation signals occurring during the formation of cracks in the rocks is proposed as a criterion of this tendency estimation. It is demonstrated that the more rock tends to brittle fracture, the greater the level of surface energy density is recorded in the formation of cracks.

References
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