地面堆载对坚硬地基和软土地基中沟埋式天然气管道的影响差异评价

Evaluation of the Effect of Landfilling on Trenching Natural Gas Pipelines with Solid Foundation and Soft Foundation

长输油气管道上方弃土堆载现象是管道管理中常遇到的问题。考虑坚硬地基和软土地基两种情形,计算上方堆载土引起的沟埋式管道附加荷载及附加位移,结合有限元数值模拟方法,给出我国常用管径沟埋式输气管道所能承受的最大地上荷载及等效堆载土高度,并分析了其地面影响因素。结果表明:一般坚硬地基中不同规格的沟埋式管道能承受的最大地上荷载为0.27~0.82 MPa,最大堆载高度可达13.4~41.0 m,最大地上载荷与管道壁厚呈正相关,随管径的增大先减小后增大;而一般软土地基中不同规格的沟埋式管道能承受的最大地上荷载约为0.20~0.58 MPa,最大堆载高度为10.1~28.9 m;最大地上载荷与堆载土作用时间和软土层厚度呈负相关,与地基土的压缩模量呈正相关;管道规格相同时,软土地基上的管道能承受的最大地上荷载普遍小于坚硬地基。

Landfill of construction rubbish above long-distance oil and gas pipelines underground becomes a common problem in the realm of pipe management.In consideration of solid foundation and soft foundation,we calculate the additional load and displacement of trenching pipelines caused by landfill combining with the finite element numerical simulation method,offer the maximum upload and the equivalent landfill height of the trenching gas pipelines with common pipe diameter in China,and analyze the influencing factors.The results indicate that the maximum upload that trenching pipes of different specifications can bear is 0.27~0.82 MPa and the equivalent maximum height is 13.4~41.0 m in the ordinary solid foundation.The maximum upload is positively correlated with pipe thickness.It decreases first and then increases with the increase of caliber.In the ordinary soft soil foundation,the maximum upload that trenching pipes of different specifications can bear is 0.20~0.58 MPa,and the equivalent maximum fill heights is 10.1~28.9 m.For pipes of the same specifications,the maximum load and the landfill height in soft foundation are generally smaller than that in solid foundation.The maximum load on the pipelines is negatively correlated with load time and soft soil thickness,and positively correlated with the compression modulus of foundation soil.