Stress Analysis Of Settlement Process Of Buried Natural Gas Pipeline With Corrosion Defects

With the continuous improvement of people’s living standards,higher requirements have been put forward for the safe operation of buried natural gas pipelines.As a country with a rich and diverse topography and a large population,the natural gas pipelines laid on soft foundations have a weak bearing capacity,and settlement will occur as time goes by.It is difficult to avoid pipeline corrosion after a long time of operation.a strong foundation.This paper studies the stress analysis of the buried natural gas pipeline with corrosion defects during the settlement process,hoping to get a more practical method for evaluating the residual strength of the pipeline when such a situation occurs,so as to provide theoretical guidance for pipeline designers,construction personnel and operation managers.On the basis of summarizing the relevant theories and methods about settlement and corrosion at home and abroad,combining with the actual engineering data and considering the interaction between buried natural gas pipeline and soil,this paper uses professional nonlinear finite element software to analyze the stress state of buried natural gas pipeline with corrosion defects in the settlement process.The main tasks include:(1)Evaluation methods of corroded pipeline with defects: Starting from the nature of corrosion,the existing evaluation methods of corroded pipeline were carefully inquired and summarized,the differences and good or bad of each method were analyzed by observing the differences of evaluation formulas,and finally chose the best method.Evaluation method close to the actual situation;(2)Establish a mechanical model based on the settlement theory: From the perspective of elastic mechanics,the theoretical stress analysis of the buried natural gas pipeline is carried out.During the analysis,some simplifications or assumptions are made on the pipe-soil mechanics model.Then the reliability of the finite element method is verified by comparing the theoretical formula with the numerical results of finite element calculation;(3)The finite element analysis method is understood from the principle,the nonlinear contact problem is analyzed in detail,the constitutive relation of pipe and soil and its interaction are elaborated,and the reason for choosing ABAQUS is revealed.Finally,the finite element results of other scholars are verified by the ABAQUS finite element,which proves that the finite element calculation model constructed is more accurate;(4)Numerical simulation: The modeling steps and the setting of loads and boundary conditions and the problems that need to be paid attention to in the modeling process are explained in detail.The stress analysis of the complete pipeline settlement process is obtained through a large amount of calculation data,and the embedding of corrosion defects is further completed.Stress analysis of the pipeline settlement process;(5)Fitting evaluation formula: Fitting the evaluation formula with the finite element analysis result data and verifying the correctness of the formula,which is used to evaluate the residual strength of the settlement of buried natural gas pipelines with corrosion defects.This evaluation formula provides better help for the safety analysis of pipeline mechanics.