Mechanical Properties of Buried Polyethylene Gas Pipelines under Vehicle Loads
Vehicle load has a significant impact on the stress and strain of gas pipelines with defects.To study the mechanical responses of buried pipelines with scratch defects under vehicle load,a test platform of"ground video capture+underground sensor acquisition"was set up,and a three-dimensional mathematical model including load,internal pressure,defect depth coefficient,and vehicle speed was established.The rationality of the numerical model was verified through tests.The influences of various factors on the pipelines were analyzed,and the mechanical response characteristics of the defective polyethylene gas pipelines were clarified.The results show that,under the actions of the vehicle,the tensile stress in the opposite directions is generated on the upper and lower ends of the scratch,resulting to the stress concentration at the defect.The stress decreases from the center of the scratch front to both ends.The greater the defect depth factor,the more obvious the stress concentration.The maximum stress of the pipelines increases with the increase of load,internal pressure,defect depth,and speed,but the speed influence on the stress is relatively small.Based on the Von-Mises theory,the ultimate bearing capacity of the pipelines with defects was analyzed.The ultimate bearing capacity of the pipelines laid across the road is less than that laid along the road.With the same internal pressure,the greater the defect depth coefficient,the smaller the ultimate bearing capacity of the pipelines.With the same defect depth coefficient,the smaller the internal pressure,the larger the bearing capacity.
Scratch DefectPolyethylene Gas PipelineBuried PipelineStress ConcentrationUltimate Bearing Capacity
万方数据
维普
