【摘要】 活动断层是地震区天然气长输管道的主要威胁,断层作用下管道会发生轴向和垂向位移,导致管道内产生较大的应变而失效,断层作用下管道应变的准确计算对跨断层区管道的设计与安全评估具有重要意义。现有的针对跨断层区管道应变计算方法主要针对管道受拉情况,缺乏对受压情况的考虑。为此,基于非线性有限元法,给出了管道受压时(穿越角大于90度)的跨断层区X80钢管压应变数值计算模型,分析了直径、壁厚、内压、土壤特性、穿越角5种主要参数对设计应变(最大压应变)的影响规律,基于有限元数据,拟合得到了受压X80钢管设计应变回归计算公式,与"西气东输二线"工程实际工况有限元结果的对比,验证了回归公式的准确性。该回归公式为穿越断层区X80钢管基于应变的设计与安全评估提供了一定的参考。更多还原

【Abstract】 Active faults pose threats to the long-distance oil &gas pipelines cross the seismic zones and the axial and vertical displacement of pipes will occur under the action of faulting,resulting in the pipe’s failure by agreat inside strain.In this case,the accurate calculation of the strain in the pipe is of great significance to the pipe design and security risk assessment.However,the existing methods only focus on the pipeline in tension but not under stress.In view of this,based on the non-linear FEM,a mathematical model was established for the X80 steel pipeline crossing an active fault with a crossing angle of over 90 degrees.And the influencing rules of pipe diameter,wall thickness,inner pipe stress,soil rigidity,and crossing angle on the design strain(the maximum compressive strain)were also analyzed.In combination with the FEM data,a regression equation was proposed for calculating the design strain of the X80 steel pipeline in this case,and the accuracy and feasibility of which were verified by many numerical examples from the West-to-East PipelineⅡ Project.This equation provides valuable reference for the pipe design and security risk assessment for the X80 steel pipe across active faults.更多还原