Estimation of the Corrosion Activity of Cryopegs on the Example of Soil Conditions of the Yamal Peninsula
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SOIL MECHANICS ESTIMATION OF THE CORROSION ACTIVITY OF CRYOPEGS ON THE EXAMPLE OF SOIL CONDITIONS OF THE YAMAL PENINSULA
UDC 551.345 A. A. Shimanov* and I. A. Komarov Lomonosov Moscow State University, Moscow, Russia, *Corresponding author Email: [email protected].
On the basis of experimental data on the chemical composition and concentration of highly mineralized soil solutions of the Yamal Peninsula, as well as theoretical developments, including simulation of the process of cryogenic metamorphism of solutions when the temperature and pressure conditions change, a method for estimating the corrosion activity of cryopegs to materials of foundations and underground utilities is proposed.
Introduction A rather large number of publications [1-6] are devoted to the estimation of the corrosion activity of frozen soils. They indicate that the corrosion rate of materials of foundations and other utilities in frozen soils can reach the corrosion rate in non-frozen ones. In saline frozen rocks, the corrosion activity of their pore solutions increases sharply [7]. Estimation of the corrosion activity of highly mineralized low-temperature solutions, or cryopegs, to the materials of foundations and underground utilities is of great practical importance. The term "cryopeg" has an ambiguous interpretation in the literature. The most common and accepted by the authors is the definition introduced by N. I. Tolstikhin: "Cryopegs (cryohaline waters) are natural saline waters of negative temperatures" [8]. According to studies [9], the region of widespread distribution of saline frozen soils and cryopegs of Western Siberia is located north of the latitude of the Novy Port village on the Yamal Peninsula (67°40'N). They lie at different depths in the form of isolated lenses that have no connection with each other, surface and ground waters. Saline frozen Quaternary rocks of the Arctic coast are, as a rule, of marine origin, therefore, in their chemical composition, cryopegs are close to sea waters, their salinity is 10-160 g/l, the composition is sodium chloride with the presence of sulfates [10]. In the regulatory documents in force on the territory of Russia, the corrosion activity of groundwater is estimated mainly by its chemical composition, which is determined fragmentarily during engineering surveys. However, both in cryopegs and pore solutions of saline rocks located in the layer of annual amplitudes, which contains foundations and underground utilities, processes of cryogenic metamorphism can occur at the stages of construction and operation of the structure. These processes, first of all, are associated with periodic changes in the natural temperature mode of the layer, as well as with the influence of various types of mechanical and thermal industrial loads (operation of soil thermal stabilization devices, the thermal effect of engineering structures, a change in the snow accumulation mode, etc.). Cryogenic metamorphism is understood as a set of physicochemical processes, such as:
Translated from Osnovaniya, Fundamenty
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