FORECASTING THE LONGITUDINAL MOVEMENTS OF UNDERGROUND PIPELINES

Main pipelines laid in low-bearing soil conditions are subject to changes in their design position, which affects the reliability of natural gas transportation. Achieving and maintaining the required reliability of the linear part of main gas pipelines is of particular importance. Emergency failures usually lead to large gas leaks into the atmosphere and undersupply to consumers, significant costs for the restoration of main gas pipelines. Special technical solutions to achieve the required stability and reliability of pipelines in low-bearing soils are need. Thus, longitudinal movements of existing gas pipelines occur, which leads to the appearance of longitudinal forces and, as a consequence, to an increase in the stress state of gas pipelines and possible destruction of pipes. A significant duration of the increase in longitudinal displacement of gas pipelines indicates that the cause of these changes in the pipeline position are the rheological properties of soils. Forecasting the increase in longitudinal movement of main gas pipelines will allow determining the pipeline operating time during which these movements will occur, which will allow planning repair work on potentially hazardous sections of main gas pipelines. In this regard, the article proposes a method for calculating the longitudinal movements of underground pipelines. Calculations of changes in the values of longitudinal movements of pipelines and changes in the deflection of a potentially hazardous section, taking into account the operating time of the pipeline are made. Conclusions about the need to take into account the strength characteristics of various backfill soils along the length of the pipeline are made.