Instrumental methods of examining the underwater crossing of TGPL across the river Lena and evaluating the changes in its stress-strain state

Abstract The article considers the instrumental methods of examining the underwater crossing of the trunk gas pipeline across the river Lena designed to determine its planned-high-altitude position, on the basis of which the stress-strain state of its elements is calculated. The following instrumental methods of examination are described: profile sounding using the OKO-2 GPR, examination of the river Lena bottom in the area of the underwater gas pipeline using the Hydra 500E side-scan sonar, determination of the actual planned-high-altitude position of the floodplain part of the underwater crossing of TGPL by means of the RD-8000 line locator. Based on the results of monitoring changes in the planned-high-altitude positions of the underwater crossing of the Hatassy-Pavlovsk trunk gas pipeline obtained by these methods, the basis for assessing the dynamics of the stress-strain state (SSS) of welded joints are summarized. Further in the article, the main principles of the assessment of the stress-strain state of pipe welded joints of the underwater crossing of TGPL across the river Lena are formulated, combining the results of on-sight investigations of the planned-high-altitude position of the gas pipeline.