Operation of permafrost conditions as a basis of stability of the urban Arctic territories

Abstract:

Mass deformations of buildings and structures are noticeable in the permafrost zone of Russia. The results of permafrost monitoring show the rise of the permafrost temperature that increase the degree of instability of the upper horizons, which stimulates ”warm” cryogenic processes. In the native Arctic settlements, almost all buildings and life support systems are in a critical state, in such objects in Russia, the degree of deformation varies in the range from 20 - 25 to 70 - 80%. Our field studies showed that in the last 25 - 30 years, 60% of objects are characterized by tendencies towards a decrease in the bearing capacity of frozen foundations. 80-85% of permafrost degradation in cities connected with the negative impact of tehnogenesis, the rest - with climate warming in the Arctic.

The main task for now is the need to “operate” the permafrost situation to ensure the sustainability for the engineering infrastructure. The research has shown that control methods should be divided on 3 main parts: 1) temperature regulation to ensure the required bearing capacity of the basements; 2) mitigation of dangerous cryogenic processes in urbanized areas; 3) protection for parts of underground structures, laying in the active layer from corrosion. Important aspect is the use of geotechnical techniques: selection of engineering methods depending on permafrost condition (principle of using the basements, density, layout of objects, etc.); regulation of the regime of snow deposits; reduce of thermal and power impacts on permafrost. Engineering and geocryological operational methods can be as follows: a) changing the conditions of heat and mass transfer between atmosphere and permafrost basements (cold ventilated cellars, snow removal, drainage systems from a surface, etc.); b) active impact (deep coolers include thermopiles etc.) on the soil in order to provide a low temperature permafrost and to increase bearing capacity of frozen foundations. Our investigations have shown the effectivity of a complex approach for permafrost “operation”.

The research was supported by the RFBR grant No. 18-05-60080 “Hazardous nival-glacial and cryogenic processes and their impact on infrastructure in the Arctic”.