ISSN 0021-8944, Journal of Applied Mechanics and Technical Physics, 2018, Vol. 59, No. 1, pp. 112–119.
Pleiades Publishing, Ltd., 2018.
Original Russian Text
DETERMINING THE PARAMETERS OF MICROCRACKS
FROM THEIR ELECTROMAGNETIC RADIATION SIGNALS
UDC 550.3 + 551 + 622
V. D. Borisov
Abstract: This paper proposes a model for determining the characteristics of the evolution of the
microcrack ﬁeld in a loaded rock sample from electromagnetic radiation signals. Calculations were
made, whose results were summarized in the form of spatial-temporal tables. Factors determining
changes in the hierarchy of microcracks were established. The adequacy of the model was veriﬁed
using the Zhurkov concentration criterion. Regions of scale invariance were revealed in graphs of the
concentration of microcracks versus their size in logarithmic coordinates.
Keywords: electromagnetic radiation, deformation, spectral–temporal analysis, concentration cri-
terion, spatial-temporal analysis, logarithmic scale invariance.
Various applied problems of rock mechanics and mining engineering require the development of adequate
models for predicting the behavior of geomaterials and structural materials under the action of various forces. It
is noted  that the main factor responsible for the fracture of objects and the emergence of earthquakes is the
evolution of microcrack ﬁeld in the earth under the action of stress concentration. This evolution leads to an
enlargement of microcracks and the formation of new regions of increased fracturing and development of main
cracks. Three regularities in the evolution of microcrack ﬁelds were formulated in .
1. The development of a system of cracks in the region of nucleation of an earthquake due to an increase in
the volume density of microcracks through an increase in the size of cracks and a decrease in their number, resulting
in main fractures.
2. The gradual evolution of small cracks into larger ones and the achievement of a certain critical number
corresponding to the Zhurkov concentration criterion :
Here N is the number of cracks of size L, K
is the critical average distance between cracks, and N
volume concentration of cracks.
If the average distance between cracks becomes smaller than the critical value, there is a change in the entire
system of cracks with an increase in their average sizes and a decrease in the average volume concentration. The
cracks are mainly localized in the region of nucleation of macrofracture. This regularity is universal for any scale
level and any loading regime.
3. Change in some characteristics of the medium in the emerging focus, and the occurrence of anomalies of
a number of geophysical ﬁelds during the change in the crack system.
In this paper, which is a continuation of [4, 5], we propose a model for determining the characteristics of the
evolution of microcrack ﬁelds in loaded samples based on electromagnetic radiation (EMR) signals.
Teplosnabzhenie, Belovo, 652612 Russia; email@example.com. Translated from Prikladnaya Mekhanika i
Tekhnicheskaya Fizika, Vol. 59, No. 1, pp. 129–137, January–February, 2018. Original article submitted July 13,
2016; revision submitted November 11, 2016.
2018 by Pleiades Publishing, Ltd.