Stress Analysis And Numerical Simulation Of Long-distance Natural Gas Pipeline In Desert

The Taklimakan Desert is rich in oil and gas resources,of which the gas reserves account for more than 1/5 of the country.With the implementation of the project of "transporting gas from west to east",the economic development of Xinjiang and the areas along the central and western regions has been greatly speeded up,and financial revenue and employment opportunities have been increased accordingly,bringing huge economic and social benefits.However,the climate environment of Taklimakan Desert is bad,the stratum is complex,and due to the influence of perennial wind and sand weather and sandstorm,wind erosion sand burial and displacement occur in the operation of natural gas pipeline,which directly threatens the safe operation of long-distance pipeline.In this paper,aiming at the stress safety of desert gas pipeline,taking a gas pipeline in the hinterland tower of Taklimakan as the analysis object,the stress state of the pipeline under the action of wind erosion is investigated by using the finite element analysis method.by using the research method of theoretical analysis and numerical simulation,the finite element model of pipe-sand-soil interaction is established to reveal the stress of the pipeline.The following studies have been carried out:(1)The stress of the pipeline under various natural disasters and engineering factors is analyzed.Through the basic theory and calculation formula,the stress of the pipeline under different stress is analyzed concretely,the Von Mises yield criterion is adopted for the buried pipeline,and the failure judgment criterion based on strain is used to judge the respective safety state of the wind-eroded sand buried pipeline,so as to ensure that the stress and strain of the pipeline under stress are in the allowable range.(2)The stress state of buried natural gas pipeline in desert under the combined action of different physical characteristics of sand,internal pressure,temperature and internal pressure and temperature is analyzed.The results show that the greater the compression modulus of sand is,the safer the pipeline is in the soil.The increase of gas transmission pressure increases the equivalent stress of the pipeline.When the gas temperature increases,the maximum equivalent stress of the pipeline increases;under the combined action of internal pressure and temperature,the maximum equivalent stress of the pipeline increases obviously and appears in the inner wall position of the pipe at the end of the section.(3)The stress of wind-eroded sand buried pipeline under internal pressure,temperature and different sand transport pressure is analyzed.Under the influence of wind erosion,the sediment transport pressure on the surface of the pipeline will change.The results show that the equivalent stress of the pipeline increases with the increase of the sediment transport pressure;when considering the internal pressure,the equivalent stress of the XOZ plane of the pipeline increases at first and then decreases with the increase of the sediment transport pressure;when the internal pressure and temperature act together,the equivalent stress of the pipeline increases with the increase of the sediment transport pressure,the maximum stress in the X axis direction appears on the outer surface of the pipe wall,and the maximum stress in the Y axis direction appears on the inner surface of the pipe wall.(4)The bottom displacement of pipe jacking increases with the increase of sediment transport pressure,and the strain of pipeline increases with the increase of sediment transport pressure,among which the strain of pipeline under the combined action of internal pressure,temperature and different sediment transport pressure is the largest.(5)The stress of wind-eroded partially suspended pipeline under internal pressure,temperature and wind load is analyzed.The results show that when considering the internal pressure,the force of the pipeline under the ultimate wind load is safe,and when the internal pressure and temperature are acted together,the maximum equivalent stress and strain of the pipeline in summer is higher than that in winter.