DOI: 10.7256/2453-8922.2023.4.69178

EDN: XGQFQH

Abstract: The subject of research is the underground structures of the cryolithozone (permafrost zones). The design of such structures, in particular the choice of space-planning solutions, methods and means of fastening rocks, unlike structures located not in frozen rocks, has a number of features and is associated with the need to take into account the zone of thermal influence of chambers operated with different thermal conditions constantly or periodically. For example, when changing the type of thermal regime in the chambers in cases of natural or man-made accidents and catastrophes. The purpose of the research was to determine the zone of thermal influence of a single chamber of an underground cryolithozone structure, depending on the type of fastening used (in the presence and absence of a thermal protective layer) and the duration of the operational period, using various calculation formulas. To achieve this goal, three types of formulas were studied that determine the dependence of the dimensionless radius of thermal influence of chambers on Fourier and Bio criteria. Multivariate calculations were performed using the formulas, which are presented in the form of 3D graphs. The analysis of the performed calculations showed that the calculations for all three formulas give similar results in a fairly wide range of changes in the initial parameters. Moreover, the formula, which does not take into account the influence of the Bio number on the radius of thermal influence, gives a certain calculated margin. In general, it is shown that the higher the value of the Bio number, the less its effect on the depth of the thermal influence zone of the underground chamber. Small values of the Bio number (up to 5-6) are typical for cameras that are fixed with sprayed concrete or have special heat-protective coatings.It is established that when choosing space-planning solutions for underground structures to assess the influence of the thermal factor, it is quite acceptable to use an approximate formula to estimate the radius of the thermal influence of a single chamber. The scientific novelty lies in establishing the scope of the studied formulas for predicting the radius of the zone of thermal influence of cameras with various types of fastening and thermal protection.

DOI: 10.7256/2453-8922.2023.4.69256

EDN: IGQCMY

Abstract: The study of exogenous processes and their effects on natural and anthropogenic systems is a very important aspect for the development of Arctic territories. One of these processes is thermal erosion, which is widespread in the Yamalo-Nenets Autonomous District due to the presence of permafrost in the vast majority of its area. The main prerequisites for the manifestation of thermal erosion processes can be divided into several groups of factors. Firstly, the geomorphological characteristics of the territory play a key role: the lengths and slopes. Secondly, the lithological and granulometric composition of rocks, as well as ice content and temperature, determine the resistance of the soil to the thermal and mechanical effects of flowing water. Thirdly, the amount of precipitation is an important factor, especially precipitation in winter and heavy rainfall in summer. They contribute to a high concentration of runoff in short periods of time, which leads to rapid destruction of rocks and the removal of large volumes of loose material. Finally, the fixation of the top layer of soils by the root system can be considered the main reason that counteracts the development of thermal erosion. The purpose of this study is a prognostic assessment of the risks of the development of thermal erosion processes in the context of the observed climate warming. To assess the risks, data from climate modeling of the Yamalo-Nenets Autonomous District for the middle of the XXI century were used for an ensemble of climate models included in the CMIP6 project. The analysis of Google Earth satellite images and information about the geological and geomorphological features of the region are used for zoning the territory in terms of dynamics and dangers of thermal erosion. The result of the study was the compilation of a map of the Yamalo-Nenets Autonomous District by categories of risks associated with thermal erosion processes. It is shown that in the perspective of several decades, more than 50% of the region's area is subject to intensification of thermal erosion destruction of soils, which requires careful planning of economic development and design of protective structures. An attempt has been made to assess the impact of erosive and thermoerosive effects on the natural environment of the Yamalo-Nenets Autonomous Okrug due to climate change using the recommendations of this assessment by Order of the Ministry of Economic Development of the Russian Federation dated 05/13/2021 N 267. Climatic factors can seriously enhance the causes and negative consequences of the development of thermoerosion, while local manifestations should be assessed using field data based on the calculation methods.

DOI: 10.7256/2453-8922.2023.4.69058

EDN: IHJPRJ

Abstract: This paper describes the results of field measurements of methane and carbon dioxide fluxes from natural and anthropogenic-modified ecosystems located on the Norilsk industrial district. Previously, such studies have not been conducted in the area. The study points are located in different landscape regions determined by various conditions of permafrost formation. Most of the study area is located within the zone of predominantly continuous permafrost distribution. Six landscape regions were identified. Methane and carbon dioxide fluxes were measured at selected key sites typical for each region. When selecting the study points, the variety of conditions affecting methane and carbon dioxide emissions was considered. First, these include soil type (mineral or peat) and local moisture conditions. Methane and carbon dioxide fluxes were measured by dart static chamber method. Measurements of greenhouse gas concentrations in the chamber were carried out by a portable gas analyzer Li-7810 (Li-COR, USA). The results obtained show significant variability in greenhouse gas emissions for different ecosystem types. Methane uptake by soils is recorded on mineral soils and dry parts of bog ecosystems. Positive methane emissions are typical for watered areas of bog ecosystems and lakes with maximum values in the hollows. Methane fluxes range from slightly negative in dry bog areas with a median of -0.026 mgCH4/m2/h to emissions of 0.802 mgCH4/m2/h as the median for watered areas of bog ecosystems. Carbon dioxide fluxes are inversely correlated with the ecosystem moisture content and have a range from 51.6 mgCO2/m2/h (median for lakes) to 576 mgCO2/m2/h (median for mineral soils). A medium strength correlation was found between surface air temperature and intensity of methane uptake by mineral soils was found. Probability density distributions of methane and carbon dioxide fluxes have different forms.

DOI: 10.7256/2453-8922.2023.4.68845

EDN: ICLKJB

Abstract: The second decade and the beginning of the third decade of the XXI century in yedoma research were characterized by a variety of high-precision measurements of gas inclusions, molecular biomarkers, and DNA. The purpose of this paper is to analyze the most notable publications of 2010–2023 devoted to radiocarbon dating and stable isotope studies of yedoma in the Russian and North American Arctic. AMS dating and stable isotope analysis continued at Lomonosov Moscow State University (Yu.K. Vasil’chuk, A.C. Vasil’chuk, N.A. Budantseva, I.D. Streletskaya, Ju.N. Chizhova, J.Yu. Vasil’chuk), especially detailed on the yedoma of Batagay, Seyakha, Kotelny, and Faddeevsky islands. Active research was continued by the participants of the Russian-German expedition (A. Yu. Derevyagin, A. I. Kizyakov, S. Wetterich, T. Opel, J. Strauss, G. Grosse and L. Schirrmeister) on the yedoma sections of the New Siberian Islands. They studied the Batagay yedoma together with J. Murton and K. Ashastina. Researchers from the University of Fairbanks (M. Kanevskiy, Y. Shur, M. Jorgenson, and E. Stephani) studied in detail the yedoma of the Itkillik River valley, as well as new yedoma sections in the Fox Tunnel, where radiocarbon and isotope studies were also carried out by M.S. Lachniet and A. Sloat from the University of Las Vegas. Research has begun on molecular biomarkers and DNA (E. Willerslev, T. Jørgensen) in yedoma. The study of PAHs in yedoma ice wedges has also begun (Yu.K. Vasil’chuk). It is emphasized that isotopic data is not an end in itself for research; the next step, paleotemperature reconstruction based on these data, is necessary and logically justified. The accuracy and reliability of the proposed paleotemperature-isotope equations are considered.

DOI: 10.7256/2453-8922.2023.4.68814

EDN: ICMZSC

Abstract: The object of study is to assess the state of engineering-geocryological monitoring of geotechnical systems (GTS) of highways in the area of permafrost distribution. The subject of the study is a set of measures to collect, process and accumulate data on road deformations, identify the causes of their occurrence and make decisions to eliminate them. The authors consider in detail such aspects of the topic as the causes of deformations of highway objects in different geocryological conditions. Particular attention is paid to the analysis of various options for obtaining primary information. From the very beginning of operation, highways in the permafrost zone are subject to intense deformations, which resume after repair and restoration work. The main conclusions of the study are: deformations on highways in the permafrost zone are caused by a complex of reasons associated with intense phase transitions of water in rock strata, which fundamentally distinguishes them from similar geosystems formed in more southern regions; engineering and geocryological monitoring of the objects under consideration must be carried out on the basis of interaction between the operating organization, the structure providing scientific support and the center for making management decisions; The existing regulatory framework does not correspond to the problems that arose during the operation of highways in the permafrost zone.