穿越克孜尔逆冲断层的输气管道抗震分析

摘要

输气管道作为1种薄壁壳体结构,逆冲断层引起的管道压缩变形容易使其破坏.本文以大北南疆输气管道工程为例,探讨了穿越克孜尔逆冲断层的输气管道地震安全问题.在确定管道穿越处的断层倾角、设防断层位错量、表征管土相互作用的土弹簧参数以及钢管容许应变等参数后,采用壳有限元方法,分析了穿越克孜尔逆冲断层的输气管道变形反应.分析结果显示,管道在逆冲断层作用下以压缩应变为主,管道内的最大轴向压缩应变的幅值随着交角的减小而减小.在通过探槽等方法确定断层活动位置后,该管道若以小于或等于11°的交角通过克孜尔断裂,断层引起的最大轴向压缩应变和拉伸应变均在管道相应的容许应变范围内,满足相关规范的抗震要求.%As a thin-walled shell structure, the gas supply pipeline is easy to be damaged with large compression deformation caused by thrust fault movement. Taking the Dabei-South xinjiang pipeline project as an example, this paper discusses the seismic safety of gas pipeline crossing the Kezil thrust fault. The shell finite element modal was used to analyze the large deformation reaction of the gas pipeline under this thrust fault after determining the fault plane inclination angle, the fortified fault displacement, the soil spring parameters representing the pipe-soil interaction and the allowable strain of the steel pipe. The FEM results show that the main strain response of the pipe under thrust fault movement is the compression strain, and the amplitude of the maximum axial compression strain in the pipeline decreases with the decrease of the intersection angle.We found that in order to meet the requirements by the national seismic code of oil/gas pipeline, the maximum axial compression strain and tensile strain caused by the fault have to be within the permissble strain range of this pipe when the crossing angle is less than or equal to 11°.