地震断层作用下的埋地管道等效分析模型

地震作用下，活动断层附近的埋地管道易发生强度屈服、局部屈曲或整体失稳等形式的破坏，建立准确、高效的埋地管道在断层作用下的计算模型，对管道的抗震设计和震后安全状态评估具有重要的实用价值。本文采用非线性弹簧模拟远离断层处埋地管道的反应，基于管土之间小变形段管道处于强化阶段，提出一种改进的管土等效分析模型，进一步减小了管土之间大变形段的分析长度，从而提高了有限元分析效率。该模型采用ALA推荐的方法计算管土间的滑动摩擦力，可以考虑土体种类的影响；用Kennedy方法确定管道的计算长度。通过与精确模型比较，验证了管土等效模型的合理性和有效性。

An Equivalent Analytical Model of Buried Pipelines Subject to Fault Movement

The failure of buried pipelines was observed adjacent to active faults due to the movements of fault during earthquakes. The main failure modes include strength failure, local bucking, and integral destabilization. An accurate and efficient analysis model for a buried pipeline subjected to fault movements is of significance for seismic design of buried pipelines and safety evaluation after an earthquake. Lots of theoretical and numerical methods were developed to obtain the response of buried pipelines under fault movements. Especially, finite element method is employed to simulate pipe and soil interaction under fault movements. The assumption that only axial displacement shall take place for the part of the pipe with small deformation between pipeline and soil is proposed and proven by FE analysis in the paper. A nonlinear axial spring located on each end of the pipe is utilized to simulate the response of a buried pipeline far away from fault. Then, an updated pipe-soil equivalent model is used to decrease the analysis length of the part of the pipe with large deformation between pipeline and soil. The soil resistance per unit length of pipe is calculated with the recommendation method from the standard of American Lifelines Alliance. The effects of soil types, interaction between pipe and soil, and material nonlinearity of pipe steel are considered in the model. Kennedy method is introduced to obtain the calculating length of a pipeline. The results of the equivalent model proposed in the paper are compared with some models of a buried pipeline subjected to strike slip faults.