Stress-strain analysis of pipelines laid in permafrost

P Burkov,S Burkova,Van Yan‘Nan’

doi:10.1088/1755-1315/43/1/012080

Abstract

Increasing reliability of pipelines becomes a real challenge at all stages: design, construction and operation of pipeline systems. It is very important to determine the behaviour of the constructed pipeline under the operational and environmental loads using the design model in accordance with that one adopted in the rules and regulations. This article presents the simulation of pipeline in permafrost. The evaluation of the stress-strain state is given herein and the areas of the stress concentration are detected with the account for different loads occurred during the pipeline operation. Information obtained from the assessment of the stress-strain state of the pipeline allows determining sections in pre-emergency state (even before damages) and take all the necessary measures for eliminating them, thus increasing the pipeline system reliability. It is shown that the most critical pipeline cross-section is observed at the point of transition from one environment to another. The maximum strains decrease the level of the pipeline reliability. The finite element model is presented to determine the pipeline sections in pre-emergency state.

Highlights

The total length of the main pipelines in Russia is currently about 50 thousand kilometers
Despite the fact that the problem of the pipeline safety is constantly the focus of attention, over 40 thousand pipeline malfunctions and accidents occur annually in Russia, the losses being over 3% of the total volume of oil and gas production
The strength analysis allowing for the real operating conditions, is one of the main procedures that assure the high reliability of the pipeline

Summary

Introduction

The total length of the main pipelines in Russia is currently about 50 thousand kilometers. The assessment of technical conditions of pipelines must include monitoring of their stress-strain state during the operation. One of the main factors that define the operating reliability of underground pipelines is the soil-pipe interaction system. Beyond-design loads can be detected at the stage of construction and during the operation by measuring the stress-strain state of the pipeline. As it is known, the main oil fields in Russia are located in West Siberia and the Far North. The investigation and forecasting of the stress-strain states of the underground pipelines is a relevant problem nowadays. The original state of the underground pipeline is determined by the position of the pipes laid in a frozen soil, and their stress-strain state should be analyzed with the account of the mechanical-andphysical properties of frozen soil [8]

Results and discussion

Steel composition

Conclusions