Mechanical properties of buried pipeline under the coupling effect of temperature and uneven settlement

Once buried pipeline occurs leakage or explosion, the damage is huge.So it is very important to investigate the mechanical properties of buried pipelines under the coupling effect of temperature and uneven settlement and conduct safety svaluation.A pipeline-strata integral model was established and nonlinearly solved by the finite element analysis software ABAQUS.Then, the coupling between temperature effect and tunneling effect was realized by means of the indirect coupling method, and the stress and strain states of buried pipelines corresponding to different pipe diameters, wall thicknesses and buried depths were simulated respectively to figure out the change laws of Mises stress and vertical displacement of pipelines under the effects of different influence factors.It is shown that under the coupling effect of temperature and uneven settlement, the stress and strain states of buried pipeline are more affected by pipe diameter and wall thickness.The larger the pipe diameter, the higher the Mises stress and the smaller the vertical displacement.The thicker the pipe wall, the higher the Mises stress and the larger the vertical displacement.When the pipeline is above the tunnel and its buried depth is in a certain range, the stress and strain states of buried pipeline are less affected by the buried depth, and Mises stress and vertical displacement of the pipeline don't change obviously with the increase of buried depth.Stress concentration phenomenon appears at pipeline joints and straight pipe junctions, so attention shall be paid to the detection and maintenance of these positions in the process of actual operation.