Reliability of linear main gas pipelines after longer operation in cryolithozone conditions

Abstract

Ensuring the reliability of gas main pipelines, after long-term operation in a cryolithozone, is a very urgent task. Due to changes in the mechanical properties of metal pipes after their long-term operation, changes in spatial positions relative to design positions in permafrost, accidents and incidents have become more frequent. At the same time, the nature of damage to pipelines of gas pipelines in different regions of Russia is different. In the regions of Russia with high air humidity and soils that freeze to a shallow depth in winter, the onset of defect formation is on the surface of pipes, mainly in the form of corrosion, whereas, in areas where cryolithozone propagates, the onset of formation of defects is in the “body” of the pipe wall and an increase in these defects leads to more disastrous consequences. Also, in areas of distribution of cryolithozone, corrosion damage is rarely observed. The article deals with one of the sections of the linear trunk gas pipeline where the incident occurred in the form of pipeline discharge. The main cause of the release is considered to be the constantly changing topography of this area as a result of periodic thawing of permafrost. The existing regulatory documents on the construction of gas pipelines contain calculations, often referring to the general rules of building mechanics. Thus, the design organization may not sufficiently take into account modern developments in scientific research in the field of cold resistance and operation of gas pipelines in the areas of cryolithozone distribution under conditions of extremely low temperatures.