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Infrastructure development and oil field exploitation are facing great difficulties. This is caused by the engineering geological conditions changing and transformation of the upper part of the section due to the anthropogenic influence. The article contains the results of researching permafrost soils conditions in the bucket-type water intake facility foundation near the Taas-Yurekh River, Yakutia, Russia (the eastern block of Srednebotuobinskoye oil/gas-condensate field). As a result of the research area engineering geological conditions analysis, the geotechnical scheme was constructed, and on the base of it the soils thawing depth mathematical modelling due to the water heating influence was performed. The soils thawing depth calculation due to the heating of the water in the reservoir was performed with the TEMP/W software of GeoStudio, which is based on the finite element method. The forecast for the end of the facility lifetime was based on the temperature measurements in the reservoir and the soil surface. The calculations results show that the maximum thawing depth due to the water heating influence will be 36 meters with the lower border temperature of -1°C, and it decreases to 16 meters with -10°C lower border temperature.

The object of study is a system of protective dams in Hanoi. In the new social and political conditions of Vietnam’s transition economy, the transformation of the riverside territories is of great importance for both the city of Hanoi and the country as a whole. A special role is given to the system of dams along the Hanga River (Red), which protect the city from floods. During the long history of construction and operation of the dams in Hanoi, many cases of their damage and destruction are known. The aim of the study is to assess the sustainability of the dams, the possible mechanisms of dam stability loss due to changes in hydrological conditions are examined. By mathematical modeling, the stability of the dam slopes and filtration strength of its base soils are calculated due to an increase in time during flooding hydraulic gradient. This task was solved in the flat setting, meanwhile, filtration modeling was carried out by the finite element method, and the estimation of the dam slopes stability was carried out based on the limit equilibrium method. The mathematical modeling allowed to estimate the dam stability from two positions: 1) change of the dam slope factor safety in time during the flood period; 2) increase of the hydraulic gradient in soils of the dam base during the flood period. The results obtained showed that the reliability of the dam depends both on the thickness of the clay layer at its base and on the duration of flooding. The factors we have identified that affect the stability of dams during flood periods can be used for predicted purposes to assess their reliability.

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