跨断层埋地油气管道屈曲行为研究

Buckling behavior of buried pipeline crossing strike-slip fault

为研究断层作用下埋地管道失效模式,建立了管土耦合三维数值计算模型,分析了不同地层位错量下无压和压力管道的力学行为及失效模式。结果表明:断层运动下埋地管道发生弯曲变形,并非完全与围土接触,整个管段摩擦力并非均匀分布;随着位错量增大,管道变形曲线由S形变为Z形,同时管道轴向应力逐渐增大;当位错量大于4D时,无压管道出现两处压溃,其变形过程分为弯曲状态、临界状态、压溃状态;不同内压管道呈现出不同屈曲形貌,随内压增大,管道屈曲形貌由压溃变为皱起;当内压大于0.4P_(max)时,管道屈曲部位出现一道皱起,内压越大,起皱幅度越大;压力管道变形过程可分为弯曲状态、临界状态、起皱状态。该研究结果可为跨断层埋地管道施工设计、安全评价、维修防护等提供参考和依据。

The three-dimensional numerical model is established to study the failure modes of buried pipeline under fault displacement. Mechanical behavior and failure modes of no-pressure and pressure pipelines are analyzed. The results shows that the pipeline is not completely contact with the surrounding soil for bending deformation caused by fault, thus the friction force between the pipeline and soil is uneven distributed along the whole pipeline. With the slip amount increases, the pipeline deformation curve goes from S-shaped to Z-shaped,and the axial strain also increases. When the slip amount is more than four times of the pipeline diameter, two collapse locations appear on the no-pressure pipeline. Deformation process of no-pressure pipeline is divided into bending stage, critical stage and collapse stage. Buckling mode goes from collapse to wrinkling with the internal pressure increases. When the internal pressure is bigger than 0.4 P_(max), wrinkling appears on the pipeline, and the wrinkling amplitude increases with the internal pressure increases. Deformation process of pressure pipeline is divided into bending stage, critical stage and wrinkling stage. These results can be used for the construction design,safety evaluation and protection for buried pipelines.