Keyword: «freezing»

This article discusses the seasonal fluctuation of the pipe of the underwater passage of the main gas pipeline on the section of the Khatasskaya channel of the Lena River, during the re-formation of the main channel.Special attention is paid to the section of the coastal slope where seasonal exogenous processes occur in the form of frost heaving and thawing of the soil, which directly affect the stress-strain state of the main gas pipeline. The choice of the left bank is directly related to the fact that the layer of seasonal freezing, starting from the near-rim plot, interlocks with the zone of permafrost soils. To determine the seasonal fluctuations of the two lines of the main gas pipeline, the method of surveying the planned-high-altitude position of the pipeline was used. It is noted, that oscillations can reach up to two meters vertically, seasonally moving horizontally to the channel of the Khatasskaya channel.

A model of the geoelectric structure of the frozen soil thickness is proposed, including a layer of their transitional permafrost. Monitoring of changes in this layer is proposed to be carried out by observing seasonal changes in the parameters of geoelectric sections, obtained as a result of radioimpedance or RMT sounding. Viewing changes in geoelectric sections over time, allows you to determine the parameters of the selected layer of transitional frost as the main ones when monitoring the state of frozen soils. An indicator of the iciness of soils is proposed. Electromagnetic emission of frozen soils occurs during intensive thawing or freezing of water in the active layer. The amplitude of the field by electromagnetic emission of frozen soils is twice as large when they melt as when they freeze. The intensity and duration of the melting and freezing of soils can be estimated by the amplitude of the field created by electromagnetic emission.

This arcticle presents a hypothetical model of transformation of the porous structure of coals’ organic matter of under the influence of negative temperatures. The model takes into account various scenarios of freezing and thawing of inner water, including either the formation of additional cracks and collectors, or with the «collapse» of micro- and mesopores. The results are presented on experiments related to the study of the effect coals of different genetic types with respect to a degree of vitrinite recovery during single freezing-thawing at different temperatures (-20, -40 and -60 °C) on their mechanical strength. It is shown that for coals of genotype I characterized by high heterogeneity of structure, the processes of freezing-thawing at different temperatures lead to an increase in the mechanical strength, which may be caused by the effect of compaction of organic matter due to the effect of «collapsing» of micro- and mesopores.

The paper presents methods of evaluating the effectiveness of reactants to reduce the freezing of coal products. When choosing such a reactants, an important indicator is the dynamics of changes in their properties during freezing. It is shown that the reactants property not turning into solid (crystalline) state at temperatures -40 and -60 оС are more efficient in reducing the freezing of coals of different rank. It is noted that treatment of coals with such reactants leads to an increase in their total moisture content after freezing-thawing cycle as compared to the untreated coals.