PHYSICAL MODELING OF HIGH-FREQUENCY ELECTROMAGNETIC WAVE PROPAGATION IN ROCKS WITH ICE-FILLED FRACTURE

One of the problems in placer mining by the opencast method in the North is the determination of rock mass fracturing. Generally, fractures in loose sediments are filled with conglomerates and ice. The presence of ice complicates geological exploration by increasing amount of drilling and promotes formation of oversizes after blasting. At the present time, fractures can be detected by various geophysical methods, seismic exploration, acoustic logging and ground-penetrating radar. Seismics and acoustic logging are mostly used to study deep fractures, while ground-penetrating radar is applicable at shallow depths (to 30 m). Proper procedures and software to backup the ground-penetrating radar studies are unavailable by now. Aimed to develop criteria for detecting fractures in permafrost by ground-penetrating radar, physical modeling of GPR sounding in permafrost rock mass with ice-filed fracture is carried out. The modeling results are described. The sounding was implemented using ground-penetrating radar OKO-2 (Logis-Geotekh Group of Companies, Russia) with antenna assembly AB-1200 MHz. Conditions, parameters, sequence and procedure of the experimentation are presented. The GPR-resultant radarograms show clearly traced contrast electrophysical boundaries reflective of the structure of the model. The fre quency analysis of the radar signals has allowed identifying spectrum features of fracture filled with ice. Furthermore, the changes in the lineups of the signals reflected from the lower and and upper boundaries of ice are marked, and the Fourier spectra of the radar path in ice and sand are obtained. Based on the determined criteria, it is possible to study fracturing of permafrost using the ground-penetrating radar method.

Keywords

Ground-penetrating radar, fracturing, rock mass, physical modeling, Fourier-spectrum, radar signal, ice.

Issue number: 11
Year: 2018
ISBN:
UDK: 621.37:622.1:556.24(001.57)
DOI: 10.25018/0236-1493-2018-11-0-107-113
Authors: Prudetskiy N. D., Sokolov K. O., Fedorova L. L.

About authors: Prudetskiy N.D., Leading Engineer, e-mail: kolyageofiz2000@yandex.ru, Sokolov K.O., Candidate of Technical Sciences, Senior Researcher, e-mail: k.sokolov@ro.ru, Fedorova L.L., Leading Researcher, e-mail: lar-fed-90@rambler.ru, Chersky Mining Institute of the North, Siberian Branch, Russian Academy of Sciences, 677018, Yakutsk, Russia.

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