METHODS OF STUDYING THE PROPERTIES OF FROZEN SOILS AND PREDICTION OF THEIR CHANGES 

F. S. Karpenko ^*,  V. N. Kutergin ,  E. O. Dernova ,  A. A. Osokin 

Sergeev Institute of Environmental Geoscience, Russian Academy of
Sciences, Ulanskii per., 13, str. 2, Moscow, 101111 Russia

*E-mail: kafs08@bk.ru

Frozen soils are traditionally considered as stable formations, the change of structure and properties of which can occur only during the transition from the frozen to the melt phase state. At the same time, the results of recent scientific and practical studies show that these changes, being gradual, begin already in the frozen state. This is confirmed by the modern activation of exogenous geological processes in the permafrost zone, which is caused by climatic changes taking place at the present time. Climate fluctuations cause a natural gradual increase in the soil temperature of the permafrost zone, which leads to a change in its condition and structure. Almost everywhere, frozen soils include a gas component. It is believed that it does not have a significant effect on the properties of the host soils, provided that their frozen phase state is preserved. The results of the conducted studies show that the migration of gases in soils begins already in conditions of elevated negative temperatures, at which the soil as a whole remains in a frozen aggregate state. The intensity of this process has a significant impact on the dynamics of changes in the strength properties of frozen soils in violation of the conditions of their natural occurrence as a result of temperature exposure and the action of loads. For a reliable study of these processes, there is currently no development and practical application of new methods for determining the strength properties of frozen rocks using direct research methods, such as triaxial and shear tests. The results of such studies should serve as a basis for the design and construction of new engineering structures, as well as the adaptation of existing structures in the regions of permafrost distribution.

Keywords: cryolithozone, frozen soils, gas inclusions, gas release, investigation of the properties of frozen soils by the method of triaxial compression and shear tests

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