摘要
【目的】断层造成的永久地面位移易使埋地油气管道产生较大的弯曲与轴向变形,导致管道因受拉破裂或受压屈曲而发生失效。传统的解析法在适用性、准确性方面存在不足,亟需构建更加精准、高效的解析法对断层区管道安全状态进行快速评估。【方法】提出一种基于等效弯曲刚度的油气管道轴向应变解析法:采用线性强化本构模型模拟管材的非线性特性,并利用非线性土弹簧模型模拟土壤在管道轴向与侧向的非线性约束作用;基于管道轴向拉伸力与土壤非线性约束力,构建断层区管道大挠度变形条件下的挠曲线控制方程;考虑管道截面应力与管道整体轴向拉伸力、弯曲的内外力的平衡关系,新建大挠度变形段弹塑性变形条件下等效弯曲刚度的迭代求解算法,实现了断层区管道截面弹塑性状态的准确求解。【结果】以某穿越断层区的X80管道为例,选取断层穿越角度15°~90°的工况,以非线性有限元方法计算结果为参考值,对比国际上3种主流解析法与新建解析法,验证新建解析法对于不同穿越角度诱发的管道拉伸与弯曲变形组合工况下的适用性:在不同组合载荷条件下,新建解析法均与有限元方法模拟结果基本一致,平均相对误差为10.32%、均方误差为6.7×10^(-3),且显著优于国际上常用的主流解析法,可实现断层区埋地油气管道应变的快速、准确预测。【结论】新建解析法在计算效率、准确性方面具有显著优势,为穿越断层区的管道应变设计与评.价提供了理论支撑,并可为油气管道抗震设计标准的修订提供参考。(图6,参19)
[Objective]Permanent ground displacement from faults can lead to significant bending and axial deformation of buried oil and gas pipelines,ultimately resulting in failures due to tensile rupture or compressive buckling.Traditional analytical methods lack sufficient applicability and accuracy;thus,there is an urgent need for the development of a more precise and efficient analytical approach to quickly assess the safety of pipelines in fault zones.[Methods]An analytical method for assessing axial strain in oil and gas pipelines based on equivalent bending stiffness was proposed.The linear hardening constitutive model was used to capture the nonlinear behavior of the pipe material,and the nonlinear soil spring model was used to represent the soil's nonlinear constraints on the pipeline in both axial and lateral directions.Utilizing the axial tensile force and the nonlinear soil constraint force,the governing equation of the pipeline deflection curve under the condition of large-deflection deformation of the pipeline in the fault zone was constructed.By considering the equilibrium between the stress in pipeline cross-sections and the overall axial tensile force,along with the internal and external bending forces,a novel iterative solution algorithm for equivalent bending stiffness during elasticoplastic deformation of the pipeline in large-deflection deformation segments was established,enabling accurate solution of the elasticoplastic state of pipeline cross-sections in fault zones.[Results]An X80pipeline crossing a fault zone was examined,with operating conditions involving a fault crossing angle between 15°and 90°selected for the analysis.The calculation results from the nonlinear finite element method were used as reference values,and comparisons were made between the newly developed analytical method and three mainstream analytical methods to verify the applicability of the new approach for combined tensile and bending deformations induced by varying crossing angles.Under different combined load conditions,strong consistency was observed between the new analytical method and the finite element simulation results,with an average relative error of 10.32%and a mean square error of 6.7×10^(-3).This performance was significantly better than that of commonly used mainstream analytical methods,enabling rapid and accurate predictions of strain for buried oil and gas pipelines in fault zones.[Conclusion]The new analytical method offers significant advantages in calculation efficiency and accuracy,providing essential theoretical support for the strain design and evaluation of pipelines crossing fault zones.Additionally,it can serve as a reference for revising seismic design standards for oil and gas pipelines.(6 Figures,19 References)
作者
刘啸奔
余佳莹
付孟楷
陈朋超
张宏
LIU Xiaoben;YU Jiaying;FU Mengkai;CHEN Pengchao;ZHANG Hong(College of Mechanical and Transportation Engineering, China University of Petroleum (Beijing)//National Engineering Research Center for Pipeline Safety//MOE Key Laboratory of Petroleum Engineering//Beijing Key Laboratory of Urban Oil and Gas Distribution Technology;PipeChina Institute of Science and Technology)
出处
《油气储运》
北大核心
2025年第11期1251-1258,共8页
Oil & Gas Storage and Transportation
基金
应急管理部重点科技计划项目“油气管网系统环境安全重大风险防控关键技术研究项目”子课题“复杂载荷下管道本体失效分析研究”,2024EMST090903。
关键词
埋地油气管道
断层作用
弯曲刚度
管土非线性
线性强化模型
大挠度变形
大应变行为
buried oil and gas pipeline
fault action
bending stiffness
nonlinear pipe-soil interaction
linear hardening model
largedeflection deformation
large-strain behavior
