Stress Calculation For Deformed Pipeline Under Uneven Settlement Condition Of Gas Station

The gas station is an integral part of the long-distance pipeline system and plays a key role in the transportation and storage of gas.Condition changes occurred in the site of station would cause stress and deformation to pipeline.Once the stress and deformation of the pipeline develop to a certain extent,it will cause serious losses.Therefore,it is very important to analyze the deformation and stress of the gas pipeline.Foundation settlement is the main manifestation of changes.Settlement of the deformation can be divided into uniform settlement and uneven settlement.The uniform settlement refers to the simultaneous sinking of the pipeline and the foundation as a whole,which has little effect on the stress and deformation of the pipeline and is relatively less harmful.The uneven settlement refers to the settlement in the partial area of the pipeline and the stress and deformation of the pipeline may suffer more.The failure of most pipelines is caused by the uneven settlement.Therefore,this paper mainly studies the stress and deformation of the pipe under uneven subsidence conditions.This paper first conducts the theory analysis of buried pipelines.Based on the research results of buried pipeline at home and abroad,this paper summarizes the theoretical model,calculation formula and mechanical analysis method of pipeline earth pressure.According to the existing research progress,the theoretical calculation model of earth pressure in buried pipeline is established and the theoretical solution of earth pressure corresponding to the example is calculated.Compare the theoretical solution with the classical theory of earth pressure to determine the rationality of the theoretical solution.According to the related researches of pipe-soil interaction,the theoretical model of equivalent spring stiffness is summarized,and the calculation method of spring stiffness coefficient is defined.By comparing the results of examples,the spring stiffness coefficient calculation model suitable for this project is selected.In accordance with the depth of the pipeline set linear changes in soil pressure and nonlinear spring-loaded equivalent parameters in order to more accurately reflect pipe-soil interaction.In order to study the deformation and stress of buried pipeline effectively,this paper takes the buried pipeline of a gas station as an example to carry out the finite element modeling and calculation work.In ANSYS software,the APDL language commands are utilized to achieve the establishment of buried pipelines three-dimensional numerical model.Considering the boundary conditions of uneven soil subsidence,the parameters of the pipeline model are adjusted accordingly,and the mechanical behavior of the buried pipeline under uneven settlement condition is analyzed.The single element method was used to study the influence of various factors on the stress results of buried pipelines,considering the changes of pipe diameter,wall thickness,depth,internal pressure and elbow curvature radius.The factors that affect the buried pipe under uneven settlement are taken into consideration for the analysis of degree of influence on pipeline mechanical properties.The calculation method and conclusion in this paper provide a direct reference for stress assessment of gas station pipelines...