Mechanical Response Analysis Of Oil Pipeline Under Surface Subsidence

The demand for oil is increasing in our country.As one of the most economical and reasonable mode of transportation,the amount of pipe laying is also greatly increased.The pipeline inevitably passes through the geological disaster zones,and surface subsidence is one of the most common and frequent geological disasters.When the pipeline passes through the surface subsidence area,it is easy to occur tension,compression and distortion under the action of subsidence soil displacement,resulting in cracks,buckling,breaking and other forms of failure.which poses a great threat to the safety of the pipeline.Therefore,the paper carried out mechanical response analysis of oil pipeline under the surface subsidence,which provided research references to determine the subsidence effect on pipeline,find out the vulnerable positions of pipeline,and make effective precautions,etc.The main research contents are as follows:(1)Summarizing of the research methods of buried pipelines under the surface subsidence at home and abroad and analysing the characteristics of analytical method,numerical analysis method and experimental research.Then analysing the causes and characteristics of typical surface subsidence,and researching influence and damage characteristics of pipeline.(2)The ABAQUS finite element software was used to establish the numerical model and analyze the mechanical responses characteristics of the force and deformation of pipeline under the surface dislocation subsidence,and the most vulnerable areas of pipeline was obtained.The finite element simulation results was compared with the analytical results,and the rationality of the finite element model was verified.Then comparing and analyzing the characteristics of failure criterion based on stress and failure criterion based on strain,and based on strain failure criterion to carry out failure determination of oil pipeline under the surface dislocation subsidence.(3)Based on the results of numerical simulation analysis,the influences of subsidence depth on pipeline stress,total strain and plastic strain were discussed.Then based on four different maximum subsidence depth,the influences of pipeline wall thickness,diameter,pressure,buried depth and soil parameters on the force and deformation of oil pipeline were analyzed.(4)The mechanical response characteristics of the oil pipeline in the basin were analyzed by numerical simulation.And the force and deformation characteristics were obtained,and the main concentration areas of stress and deformation of pipelines were found.Then based on three kinds of maximum subsidence,the influences of various factors on the stress and deformation of pipeline were discussed.The sensitivity analysis based on orthonormal test was performed in multi-factor sensitivity analysis with stress and strain as evaluation indexes respectively,and the sensitivity order of factors was obtained.(5)Forecasting surface movement and deformation of XC mining area,calculating the maximum allowable subsidence,and judging the safety of the pipeline.The mechanical response characteristics of the oil pipeline under the mining subsidence were numerically simulated,and the simulation results and monitoring data were compared and analyzed.Finding out the pipeline stress concentration area and suggestions for surface displacement monitoring and pipeline stress monitoring were put forward,which can provide theoretical support for the safety evaluation of the pipe in the mining subsidence area.