Concerning the Bottom Erosion and Frost Heaving on the Section of the Underwater Crossing Route of MGL Across the River Lena

Abstract

The uneven nature of the planned-high-altitude positions (PHAP) of the gas pipelines in the floodplain of the river Lena is affected by the hydrological, natural environment, and climatic processes and such permafrost processes as heaving, thawing, and freezing.The effects of hydrodynamic and permafrost processes, heaving phenomena on floodplain areas and shore slopes together increase the non-functional loads on the underwater gas pipeline. Due to these factors, high longitudinal tensile stress arises in the welded joints of siphon pipes and facilitates accidents and incidents at the underwater crossing of MGL. A numerical experiment was performed with the initial data on the river Lena in the area of the underwater crossing of the main gas pipeline (MGL) using hydrometeorological data. The dynamics of erosion over time is presented. A change in the profile of bottom sediments negatively affects the state of the pipeline. Dangerous exogenous processes: seasonal heaving, frost cracking, thermal subsidence, thermokarst, and coastal erosion, intensify when the natural conditions are disturbed (underwater crossings).