EVOLUTION OF THE THERMAL REGIME OF THE PYROGENIC SOILS IN CENTRAL YAKUTIA

Abstract

This article discusses the thermal response of upper permafrost to anthropogenic disturbances. It presents the results of experimental geocryological investigations conducted in support of geotechnical exploration and construction of linear engineering projects. The geocryological conditions in the study area, as well as the methods of permafrost geocryological monitoring are described. The research focuseds on the upper permafrost within the depth of annual temperature fluctuations. The field observations involved repeated surveys of burned areas, including measurements of snow depth, snow density, soil properties, thaw depth, and ground temperature in the cold and warm seasons. The study aimed to explore the active layer thickness and near-surface permafrost temperatures, the variables that indicate changes to the ground thermal regime in the pipeline, railway, road and powerline corridors. The observation results demonstrated significant increases in mean annual temperature of the upper permafrost layers, as well as in seasonal thaw depth in the burning and deforestation on the burning. The depth of soil thawing in the burned areas increased every year, in places reaching the top of ice wedges and causing permafrost degradation. There are data on development of hazardous cryogenic processes causing surface deformation. The variability of the thermal regime of soils on burned and burned with felling areas depending on the stages of self-restoration of vegetation was quantitatively estimated. The research results were used in the research and construction of linear structures. The experimental data served the basis for geocryological forecast and development of recommendations for environmental management.