天然气长输管道通过高填方规划道路区的整治设计

Rectification of long-distance pipelines buried under high filling planned roads

通过高填方规划道路区的天然气长输管道,因受路基高填方沉降的影响,会导致管道力学形状发生变化,管道有可能出现局部应力集中,这将严重影响管道的运行安全。对于该类问题目前多采用建设保护涵的方式来解决,但保护涵施工困难,投资高且不满足地方政府道路施工工期的要求。为此,对高填方段管线应力进行分析,提出了整治措施并计算其安全合理性。结果表明,增大管道壁厚是可行的整改方案。进而应用ABAQUS有限元软件,用梁单元模拟管道,将管道上方的回填土视为荷载,管道下方的弹性地基模拟为均匀分布的弹簧,分析了管道的稳定性以及因规划道路高填方不均匀沉降引起的管道应力。通过应力云图可以看出,管道在沉降突变处出现了应力集中现象,如果对该区域的管道不采取合理的整治措施,管道将在运行时出现事故。ABAQUS有限元软件分析结果也表明,高填方区管道因不均匀沉降引起的应力,通过增大管道壁厚的整治方案最为经济、合理。但同时也指出,管线安全运行的根本保障还是避免管线路由敷设于高填方规划区内。

If a long-distance gas pipeline is unavoidably buried under a high filling planned road,the high fill subgrade setting will result in the change of the pipe＇s mechanical shape and the local stress concentration on the pipe,which will pose threats to the safe operation of the pipeline.Protection culverts are mostly considered to be a solution but with difficulty in construction,a high cost and inability to meet the requirements for the construction duration of the planned road project organized by the local government.In view of this,besides the scheme of increasing the pipe thickness,we analyzed the pipe＇s stability and the stress on the pipe caused by the uneven high fill setting by using the ABAQUS finite element software package,in which the pipe was simulated by the beam element,the backfill above the pipe by the stress load,and the elastic foundation underneath the pipe by the evenly-distributed spring.From the stress cloud charts,we can see the stress concentration on the pipe where a sudden change occurs in high fill setting; if without any reasonable measures taken,accidents will be inevitable in the end.The analysis results from the ABAQUS also show that the scheme of increasing the pipe thickness will be the most cost-effective and practical way to deal with the stress resulted from the uneven high fill setting above the pipe.To the best of a long-distance pipeline project,we suggest that the pipeline laying route should be avoided through the high hilling planned road as far as possible.