DOI: 10.7256/2453-8922.2023.1.40378

Abstract: The subject of the study of the proposed article is the gas component of the cryolithozone. If the solid and liquid phases of frozen rocks have been studied sufficiently deeply and systematically, then the gas component has been studied weakly and fragmentally. The object of the study is gas-saturated frozen soils, their spatial distribution and properties. Studies of recent decades have shown that the gas component plays a significant role in the structure and properties of frozen rocks. The author examines in detail such aspects of the topic as the effect of gas on the physical and mechanical properties of both thawed and frozen soils. Special attention is paid to the overlap of capillaries in the soil with gas, an increase in pore pressure, a weakening of soil consolidation and connections between soil particles. This, in turn, is expressed in a decrease in strength and density while increasing compressibility and porosity.      The novelty of the study lies in the fact that for the first time a comparative analysis of data on the content of the gas component of the pressure in it and the processes occurring in frozen rocks was carried out. A special contribution of the author to the study of the topic is that the influence of free gas on their physical and mechanical properties is shown. The relevance of the topic under consideration is due to the need to study the patterns of deformation of frozen rocks depending on the degree of gas saturation. The article analyzes the state of the regulatory framework that takes into account the influence of gases on strength and deformative properties. Their almost complete absence was recorded. The importance of taking into account the possible increased pressure in gas-saturated frozen rocks in the development of research methods and regulatory documents for their use in engineering-geological and design work is shown. The materials considered indicate that gas-saturated frozen soils are a significant and important part of the cryolithozone and their study should be carried out within the framework of an independent section of geocryology.

DOI: 10.7256/2453-8922.2021.3.35505

Abstract: The subject of this research is frozen rocks that compose gas emission funnels in the north of Western Siberia. The object of this research is the cryogenic factor that causes the formation of gas emission funnels. The authors substantiate the thesis that gas emission funnels are cryogenic phenomenon, and the processes preparing the explosion cannot be accurately interpreted without taking these features into account. The analysis of research materials on gas emission funnels, discovered in the north of Western Siberia, allows concluding that surface conditions may have a significant impact upon the formation of gas emission funnels. Special attention is given to consideration of the hypothesis of formation of gas emission funnels due to local heat penetration and gas supply from the depth. The necessary conditions are described. The article provides the examples of using geophysical methods for detecting of gas supply channels. It is concluded that gas emission funnels are the result of self-development of fluid-dynamic geosystems, which represent local, ice subsurface gas-saturated formations that are in a inequilibrium thermodynamic state with respect to the enclosing permafrost formations. The authors' special contribution consists in examination of the external and hidden mechanisms of the emergence of inequilibrium conditions od the mechanism that launches an explosion. The novelty of this research lies in the development of technique for determining the processes that cause the emission of underground gas, based on the analysis of cryogenic formations, which compose the walls of gas emission funnels.

DOI: 10.7256/2453-8922.2021.2.35500

Abstract: The subject of this research is the cryogenic formations found in gas emission funnels in the north of Western Siberia. The object of this research is cryogenic processes that prepare the explosion, which forms a gas emission funnel. The study of cryogenic structures that shape the walls of gas emission funnels is based on the structural-genetic analysis, which reveals the peculiarities of the initial cryogenic structure of frozen rock, as well as the cryogenic textures modified as a result of dynamic metamorphism. The authors examine such aspects of the topic as the general orientation of plastic and explosive deformations under the influence of high pressure. Analysis is conducted on the role of intra-ground gas filtration in transformation of the initial cryogenic structure. Special attention is given to the patterns of emergence and development of the local geodynamic system that ultimately substantiates the formation of gas emission funnel. The novelty of this research consists in the establishment of paragenetic relations between the processes of gas filtration and deformations of gas-saturated ice surface material (from viscoplastic motion to brittle fracture). The main conclusions are as follows: such external influences as increase in the temperature or pressure change thermodynamic conditions, which lead to multi-phase structural transformation of the initial cryogenic structure of the cryolithic zone; a series of plastic and explosive deformations instigates the intense heat and mass transfer, redistributing the substance in the liquid, solid and gaseous state; in frozen rocks, ice is the most deformable component, thus, most information on the processes preceding the formation of gas funnels can be acquired by studying the morphology of cryogenic formations observed in the walls of the funnels, as well as in the unthawed fragments of frozen rocks thrown to the surface. The authors’ special contribution lies in examination of the complete lifecycle of the development of selected geosystems, from the initial stage –  formation of conditions for decomposition of the gas hydrates, to the final stage – explosion and emission of ice surface material.

DOI: 10.7256/2453-8922.2019.4.30997

Abstract: The subject of this research is gas filtration in frozen rocks. For the first time, in laboratory conditions, it was possible to identify the processes that accompany gas filtration in frozen ground. Particular attention is paid to the study of deformations of primary cryogenic textures during filtration of gas under pressure. The features of the propagation of gas fluids in a frozen sample are analyzed. A comparative analysis of the cryogenic structure of frozen samples with and without gas supply has been carried out. The mechanism of pressure filtration of gas in frozen rocks is formulated. When studying frozen ground samples subjected to pressure gas, we used the methods of texture and structural studies in transmitted, reflected and polarized light. To identify changes occurring in frozen samples under pressure from gas, a comparative analysis method was used. At the same pressure, at low temperatures of the samples, filtration does not occur. Filtering begins when the temperature rises to -1 - -2 ºС. In nature, these relationships are determined by geological, landscape, and climatic conditions. For the first time, in laboratory conditions, with the help of structural studies, it was possible to identify the processes accompanying gas filtration in ice.

DOI: 10.7256/2453-8922.2019.3.29627

Abstract: The object of this research is the problem of gas filtration in permafrost formations. Currently, geocryology identifies the movement capability of gas fluids is only within the thawed formations. The subject of this study is the processes substantiating and accompanying redistribution of gas in the gas emission craters, as well as in the samples of artificial ice exposed to gas pressure. The authors examine the summarized data on the structure of craters and conditions for their emergence such as: the zones of accumulation of subterranean gas with abnormally high pressure in the permafrost strata; filtration of gas into high-temperature frozen rocks and subsurface ice; formation of gas-saturated ice soil rods and their explosive destruction. Particular attention is turned to the laboratory examination of gas filtration in frozen rocks and ice. The main research method became the comparative data analysis on the changes of properties of the frozen soils and ice as they war up within negative temperatures. Exploring the samples of ice exposed to gas pressure, the authors apply the methods of textural and structural studies in the passing, reflected and polarize light. It is established that the frozen rocks and subsurface ice allow gas filtration in the conditions of forming the corresponding ratio of characteristics of the rocks (strength, deformative, structural) that depend on their temperature and pressure of the underlying soil gas. It is revealed that the aforementioned ratio is determined by the geological, landscape and climatic conditions. With the help of structural studies, the authors are first to describe the processes accompanying gas filtration within ice in the laboratory conditions.