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Date submitted2024-05-17
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Date accepted2025-03-27
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Date published2025-03-27
Determination of impact hazard potential of rocks in the Norilsk Industrial Region
The deeper the mineral deposits developments are, the worse the mining and geological conditions become. Significant growth of stress level in the rock mass contributes to possible manifestation of rock pressure in dynamic form. The resulting task of assessment of rock impact hazard is closely related to the task of obtaining more accurate results of compression tests of samples in rigid or servohydraulic test presses using graphs of their full deformation. This approach requires special expensive equipment, considerable time resources, and sufficient core material. Therefore, it is important to have an approach that allows to assess the propensity of rocks to brittle fracture with research methods simple enough not to result in the loss of quality and reliability of the obtained results. This paper presents the results of laboratory tests of rocks from the Norilsk Industrial Region to determine their tensile and compressive strengths. Test methods involved both domestic and foreign standards for determining the value of the brittleness coefficient. The impact hazard potential of rocks was determined using the Kaiser criterion. It is found that the tested lithological types (rich sulfide ores, hornblende, disseminated ores, and gabbro-dolerite rocks), with the exception of anhydrite, have a low impact hazard potential.
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Date submitted2021-09-29
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Date accepted2022-05-11
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Date published2022-07-13
Tensor compaction of porous rocks: theory and experimental verification
Compaction in sedimentary basins has been traditionally regarded as a one-dimensional process that ignores inelastic deformation in directions orthogonal to the active load. This study presents new experiments with sandstone demonstrating the role of three-dimensional inelastic compaction in cyclic true triaxial compression. The experiments were carried out on the basis of a triaxial independent loading test system in the Laboratory of Geomechanics of the Ishlinsky Institute for Problems in Mechanics of the Russian Academy of Science. The elastic moduli of the material were estimated from the stress-strain curves and the elastic deformations of the sample in each of the three directions were determined. Subtracting the elastic component from the total deformation allowed to show that inelastic compaction of the sandstone is observed in the direction of active loading, whereas in the orthogonal directions there is a expansion of the material. To describe the three-dimensional nature of the compaction, a generalization of Athy law to the tensor case is proposed, taking into account the role of the stress deviator. The compaction tensor and the kinetic equation to describe the evolution of inelastic deformation, starting from the moment of the load application are introduced. On the basis of experiments on cyclic multiaxial compression of sandstone, the identification and verification of the constructed model of tensor compaction were carried out. The possibility of not only qualitative, but also quantitative description of changes in inelastic deformation under complex cyclic triaxial compression is shown.
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Date submitted2018-07-12
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Date accepted2018-09-09
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Date published2018-12-21
Application of the theory of wavelets for compression and filtration of geoinformation
- Authors:
- A. S. Yarmolenko
- O. V. Skobenko
The purpose of the article is to develop a detailed and accessible technology for the application of wavelets in the processing of geo-information, the subject of research is wavelet-based filtering and compression of geo-information. The research methodology is based on the modern theory of wavelets in the light of linear algebra. Research methods involve study and generalization, abstraction, formalization, mathematical modeling using computer programs compiled by the authors. After the introduction and formulation of the problem, the basic positions of linear algebra are presented, on which the content of the article is based when constructing orthonormal bases in one- and two-dimensional cases. First, the application of the general theory to the decomposition of the vector of initial data in the Haar and Shannon bases is given. Further, on the basis of the Haar basis, orthonormal bases of wavelet transforms and filtering information are constructed. The procedure for creating wavelet filters by a sequence of convolutions, the use of MSA analysis for constructing an orthonormal basis of the wavelet transform is considered. Implemented the practical possibility of wavelet filtering based on specific programs for modeling geo-information data fields and images, data compression and filtering. The result of the work is the methods of constructing orthonormal bases by various methods of wavelet transform, based on which algorithms and corresponding computer programs for geoinformation compression are compiled using the example of terrain and photographic images. The efficiency of geoinformation compression and noise filtering using wavelets was investigated. A method has been developed for determining the value of a filter depending on the accuracy of the initial geo-information, illustrated by the example of calculating the filter value for compressing information about the heights of the terrain. The same technique is recommended for image filtering.