Optimization of capital costs for pile foundations during construction of oil and gas production facilities on permafrost soils

UDK: 338.45:69:622.276

DOI: 10.24887/0028-2448-2019-11-46-49

Key words: comparison of options for the construction of foundations, design of foundations on permafrost soils, soil thermal stabilizers

Authors: N.G. Gilev (Rosneft-NTC, RF, Krasnodar), E.V. Zenkov (Rosneft-NTC, RF, Krasnodar), U.S. Poverenniy (Rosneft-NTC, RF, Krasnodar), A.D. Dubrov (Rosneft-NTC, RF, Krasnodar), D.A. Kuzmin (Rosneft-NTC, RF, Krasnodar), A.S. Melentev (Rosneft-NTC, RF, Krasnodar), V.A. Pavlov (Rosneft Oil Company, RF, Moscow), N.N. Berdnikov (Rosneft Oil Company, RF, Moscow)

The problem of finding optimal and economically justified solutions for pile foundations during construction of oil and gas production facilities on permafrost soils is becoming increasingly urgent in connection with the development of fields in Western and Eastern Siberia. Taking into account requirements of the specifications and technical documentation and also experience of design the bases are applied mainly pile with a high grillage, as much as possible limiting transfer of heat from constructions in their basis. In this article we considered the applied technique of technical and economic comparison of versions of the device of the pile foundations constructed according the 1 principle of Construction Standards and Regulations 25.13330.2012 when saving soil of the basis in a frozen status in the course of construction and during the entire period of operation of a construction. When defrosting frozen soil loses the integrity, structure and strength properties, there is an uneven draft, watering and further development of negative cryogenic processes. A solution is presented for a technical and economic comparison of the options for installing pile foundations with and without soil thermal stabilization (STS) systems directly at a design stage of the bases. Application of soil thermal stabilization, allows to reduce considerably length and (or) diameter of piles, and sometimes even to reduce quantity of piles in a grillage when saving necessary bearing capacity of piles. At the same time application of STS is not always reasonable since reduction of length of piles at the STS installation can be insignificant while application of the cooling systems demands additional capital expenditure and increases duration of installation and construction works. The right choice will provide not only economic effect, but also will ensure reliability and safety of operation of designed projects.