Development of a method for identifying cracks in permafrost rocks based on differentiation of GPR data

Abstract

Relevance. The presence of cracks significantly affects the physical and mechanical properties of rocks, which must be taken into account when planning mining operations and building mining structures. In the conditions of the distribution of permafrost rocks, characteristic of the North-East of Russia, the study of fracturing is possible using the ground penetrating radar method, which is used to assess the structure of rock masses of placer deposits. The criteria for identifying cracks based on the characteristics of GPR wave fields are currently known, and the main problem preventing the full use of the GPR method for studying cracks in subsurface layers of rocks is the significant complexity of processing and interpreting GPR measurement data. The purpose of the work is to develop a method for processing the results of ground penetrating radar measurements to identify cracks in frozen rocks. Methods. Physical and computer modeling of GPR measurements of a rock mass with a fracture, differential calculus methods for analyzing the GPR wave field structure model. Results and their scope. As a result of the research, based on an early developed model of the structure of the GPR wave field, the use of the differentiation operation for identifying cracks in permafrost rocks was justified. Special cases of rectilinear inclined and horizontal axes of in-phase of ground penetrating radar signals are considered and corresponding formulas are obtained for them. The theoretical results obtained were tested on computer and physical modeling data, as well as on field measurement data. An analysis of the features of the signals after differentiation was carried out, and the features of the original radargrams were noted, which may interfere with the reliable interpretation of the results obtained. Conclusions. In the practice of processing data from ground penetrating radar measurements, the results of the research will make it possible to more quickly identify zones of increased fracturing in rocks. In the future, it is planned to develop an algorithm and software that implements it for mapping rock fractures using ground penetrating radar data.