Concerning the Stream Turbidity During the Laying of the Underwater Crossing of the Main Pipeline Across the River Lena

Abstract

The stream turbidity significantly changes during the river bed evolution. It depends on the sediment storage, which is affected by the bottom dredging works, the construction of underwater crossings of main pipelines, bridge crossings, and others.In the present paper, we consider the change in the stream turbidity during the laying of the underwater crossings of the main pipelines (ML) across the river Lena. A significant increase in the water turbidity and the discharge of suspended sediment has been detected during the construction of linear structures intended for transporting the energy resources. The river bed erosion in the trench area is one of the factors of the decrease in the service life of the underwater crossing of ML when the siphon is trench laid across a water channel. When the bottom is scoured, and the siphon of the underwater pipeline is denuded, significant hydrodynamic loads not specified by the project are added to the operational loads. Torsional, bending, and overturning moments, as well as the phenomena of hydro-abrasive erosive wear, develop [1]. They lead to fatigue failure of individual sections of the underwater pipeline on the base metal and welded joints. It is crucial to conduct further studies to assess the deterioration degree of the ecological state of the river Lena.