Investigation of the Dynamics of Gas Emission from Frozen Soils with Change in Temperature and Pressure
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EXPERIMENTAL INVESTIGATIONS INVESTIGATION OF THE DYNAMICS OF GAS EMISSION FROM FROZEN SOILS WITH CHANGE IN TEMPERATURE AND PRESSURE
UDC 624.131.4 F. S. Karpenko,1 V. N. Kutergin,1 P. I. Kotov,2* and R. V. Sobin1 1
Sergeev Institute of Environmental Geoscience RAS (IEG RAS), Moscow, Russia; Lomonosov Moscow State University, Moscow, Russia, *Corresponding author Email: [email protected]. 2
The presence of a gas component is an important feature of the frozen soils structure, which is currently practically not studied by laboratory methods during engineering surveys. To assess the gas content and dynamics of gas emission from frozen soils, the authors have developed equipment and a technique for triaxial and shear testing of samples at different temperatures and stress states. As a result of the research, it was revealed that the gas emission begins even with insignificant changes in the frozen soils temperature. The impact of external loads reduces the temperature at which gas emission begins and affects its dynamics when the temperature changes. The strength characteristics of frozen soils after gas emission change depending on the negative temperature and the value of volumetric compression pressure. Introduction Investigation of the dynamics of gas emissions in frozen soils and during their melting is of great interest when considering the issues of greenhouse gas emissions in the Arctic regions. One of the most important issues is the assessment of methane emissions during climate change in the Arctic regions [1]. Due to the relevance of the topic, international research programs have been developed [2, 3]. The issues of the influence of gas inclusions on the properties of frozen soils are becoming more and more relevant for the objects of industrial and economic activity. In these cases, the properties of soils are affected not only by natural conditions, but also by changes in the temperature mode and the stress state of soil massifs in the course of the construction and operation of industry-related objects [4-7]. In terms of composition, frozen soils are a multicomponent system, one of the components of which, along with the mineral part, ice and water, are gas inclusions. At the same time, the features of the interaction of the gas component with the solid and liquid phases of the soil still remain insufficiently studied. According to modern concepts, the gaseous component in frozen rocks is a mixture of various gases, which mainly consists of hydrocarbon gases of biochemical, catagenetic origin and gases captured by the atmosphere [8]. According to E. M. Chuvilin [9], gases in frozen rocks can be in four main forms: dissolved, adsorbed, free, and clathrate compounds with water. Dissolved gas is in the liquid component of soils (in films of not frozen water around the particles of the organo-mineral skeleton, in the detached water of cooled rocks) and is generated due to diffusion and adsorption processes. The amount of dissolved gas depends on its solubility under given conditions. Dissolved gases signifi
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