建、构筑物下现状钢管包封保护方案对比研究

Comparative Study on Encapsulation Protection Schemes of Existing Steel Pipe under Buildings and Structures

结合实际工程,针对新建建、构筑物下存在不能迁改的现状钢管,提出柔性半包封、刚性半包封、柔性全包封、刚性全包封4种钢管包封保护方案,采用Midas-GTS有限元分析软件建立了三维数值计算模型,分别施加100kPa~180kPa附加荷载,从地面沉降、钢管最大竖向变形、钢管管壁最大环向应力三方面进行对比研究。结果表明:柔性半包封、刚性半包封保护方案可减少地面沉降、钢管最大竖向变形,但效果不显著,对减少钢管管壁最大环向应力效果不明显;柔性全包封、刚性全包封可减少地面沉降,但效果不显著,对减少钢管最大竖向变形、管壁最大环向应力效果显著,其中柔性全包封效果最佳,较无包封均减少90%以上。最终给出各包封保护方案特点,供设计人员参考。

Based on the actual project,in view of existing steel pipes that cannot be relocated under new buildings and structures,four steel pipe encapsulation protection schemes were proposed,as flexible semi-encapsulation,rigid semi-encapsulation,flexible full encapsulation,and rigid full encapsulation.Three-dimensional numerical model was established using Midas-GTS finite element analysis software,applied with addition-al loads of 100kPa~180kPa,and the results were analyzed in three aspects:land subsidence,maximum vertical deformation of the steel pipe,and maximum hoop stress of the steel pipe.The results show that the protection schemes of flexible semi-encapsulation and rigid semi-encapsulation can slightly reduce land subsidence and the maximum vertical deformation of the steel pipe,and barely reduce the maximum hoop stress of the steel pipe.The protection schemes of flexible full encapsulation and rigid full encapsulation can slightly reduce land subsidence,but remarkably reduce the vertical deformation of the steel pipe and the maximum hoop stress of the steel pipe.The flexible full encapsulation is the best scheme,which reduces by more than 90%compared with no encapsulation.Finally,the characteristics of each encapsulation protection scheme are concluded and proposed for designers.