Study On Mechanical Properties Of Corroded Pipes In Frozen Soil Region Based On Finite Element Analysis

With the proposal and implementation of national strategic plans such as the “Belt and Road”,the current international oil and gas cooperation development and utilization,that is,transnational long-distance oil and gas transmission buried pipelines and buried oil and gas has become the main Mode of transportation.However,due to the large land area of China,the distance between oil and gas production and supply is far away,the geopolitical environment through which the pipeline is designed and constructed is complex,such as desert areas,alpine hilly areas and permafrost areas.The safe operation and maintenance has caused great difficulty.As the world's third largest frozen country,the permafrost regions and seasonal permafrost regions in China account for 21.5% and 53.5% of the national area,respectively.The permafrost regions are mainly distributed in Xiaoxing'anling,Northeast,Songnen Plain and other regions.And the Qinghai-Tibet Plateau and some high-altitude areas,the built oil and gas pipelines also pass through the frozen soil areas of many places.On-site inspection found that the risk of pipeline damage in the frozen soil area is high.Considering that many sections of pipelines pass through China's permafrost regions,and during the pipeline laying and operation,due to the influence of surrounding environment and other factors,the problem of frost heaving,melting and corrosion of the soil has become an important aspect affecting the safety of this pipeline engineering.In order to ensure the stability and high efficiency of domestic energy transmission,and to continuously improve the current pipeline transmission capacity,it is necessary to study the mechanical properties of the corrosion pipeline in the frozen soil area,and then guide the design optimization of the gas pipeline.In order to analyze the stress variation of corroded pipelines in frozen soil area better and more effectively,this paper establishes a physical model of corrosion pipeline based on shell model for the environmental characteristics of permafrost regions,and studies the mechanical properties of corroded pipelines in permafrost regions.The influence of internal pressure,frozen soil action(lifting position,end tensile stress)and corrosion parameters(depth,length and angle)on the stress/strain of the pipeline,so as to understand the operation of the corroded pipeline in the permafrost zone Finally,the finite element analysis of the corroded pipeline in the frozen soil area was completed.