Finite Element Analysis On Local Stability Of Large Diameter Buried Heating Pipeline

With the rapid development of centralized heating industry,the diameter of buried trunk heating pipeline is getting larger and larger,some even reaching at 1.4meters.At present,there is a lack of systematic analysis for the stability of large diameter buried heating pipelines.In particular,the numerical analysis of local stability is seldom involved.Therefore,this paper is a valuable reference to research the local stability of pipeline.Firstly,the theoretical basis of local stability analysis of pipeline was discussed.Secondly,based on an engineering example,a three-dimensional pipe-soil contact model was established by finite element software ABAQUS to simulate and analyze the local stability of the large diameter buried heating pipeline during the warming operation.The variation of pipe displacement and stress-strain distribution during pipeline buckling was studied,and the critical temperature difference of local buckling of pipe was obtained.Finally,through the parametric analysis,the influence of three kinds of load factors of ground load,overburden load,soil friction and two kinds of pipe wall thickness defects,positioning deviation on the local stability of the pipeline was obtained and the corresponding protective measures were put forward according to the results.The conclusion shows that under the action of the ground load,the local instability is likely to occur when there is a high temperature difference in the heating pipeline with the positioning deviation.When the local buckling occurs,the deformation value of the vertical depression of the pipeline wall in the middle of the pipeline suddenly increases,accompanied by the redistribution of stress.Among the various factors that affect the local stability of the pipeline,the influence of ground load,pipeline wall thickness,pipeline wall thickness defects,positioning deviation and cover depth is great,and the influence of pipe-soil friction coefficient is small.