走滑断层位移作用下X80天然气管道的管沟合理尺寸分析

活动断层是埋地长输管道安全运行面临的主要威胁，走滑断层是常见的1种断层形式，走滑断层错动下管道会产生较大的轴向应变而引发失效。采用松散颗粒状的松砂土进行管沟回填是穿越断层埋地管道主要的抗震措施之一。为得到经济有效、适用工程的管沟尺寸，基于非线性有限元方法建立了准确的考虑管沟回填的管道穿越走滑断层数值模型,使用壳单元和实体单元模型来模拟管道和土壤，采用面与面接触算法准确描述管土接触；通过参数化计算，分析了管沟的几何尺寸对管道应变的影响，并基于经济性原则给出了管沟尺寸的建议值。结果表明:管沟坡度是影响管道应变的主要因素，工程中建设管沟时建议其管沟坡度小于1，且管道尽量浅埋，对于管沟加宽裕量可不做特殊处理。研究结果可为埋地管道的抗震设计提供参考，为管道的安全运营提供保障。

Analysis on rationality of trench geometrical size for buried X80 natural gas pipeline under strike-slip fault displacement

The active fault is one of the major threats for the safe operation of the buried long-distance pipeline, and the strike-slip fault is a typical form of fault. The pipeline under the strike-slip fault displacement may appear the larger axial strain, which may lead to the failure. The trench backfilling using the loose sand with the loose granular shape is one of the major aseismic measures for buried pipeline crossing the fault. In order to obtain the economical, effective and applicable geometric size of the trench, a numerical model on pipeline crossing the strike-slip fault with considering the trench backfilling was established based on the nonlinear finite element method, in which the pipe and soil were simulated by the shell element and solid element models respectively, and the surface to surface contact algorithm was applied in the simulation of pipe-soil interaction. The influence of the trench geometrical size on the pipe strain were discussed through the parametric calculation, and the suggested values of the trench geometrical size were proposed based on the economic principle. The results showed that the slope of pipe trench is the main factor affecting the pipe strain. When constructing the trench in the engineering, it was suggested that the slope of pipe trench should be less than 1, the pipeline should be shallow buried as far as possible, and the special treatment is not required for the widening allowance of the pipe trench. It can provide reference for the aseismic design of buried pipelines, and provide protection for the safe operation of pipelines.