湖中基坑-双排钢管桩围堰受力变形分析

Analysis of Force and Deformation of a Double-row Steel Pipe Pile Cofferdam in a Foundation Pit in a Lake

为便于施工,位于水域中的基坑工程通常需要施作围堰来保证施工场地干燥,但目前对围堰变形的研究尚不完善。以南昌艾溪湖隧道工程为研究背景,利用Midas GTS NX有限元软件,研究围堰宽度、拉杆位置对双排钢管桩围堰变形规律的影响,并通过将模拟计算结果与实测数据进行对比,验证了模型的合理性。研究结果表明:围堰宽度有一个合适的范围,过小过大均会造成围堰变形过大。在本工程中,围堰合理宽度范围为3.5~4.5 m,围堰宽度的改变对围堰内基坑开挖变形影响较小;综合两侧钢管桩变形来看,拉杆设置在围堰顶部0.8 m处时两侧钢管桩变形较小。

Cofferdams need to be used to ensure the dry construction site for foundation pit located in water areas.However,the study on cofferdams deformation is still not perfect.Based on the research background of Aixihu Tunnel project in Nanchang,Midas GTS NX finite element software was used to study the influence of cofferdam width and tie bar position on the deformation law of double-row steel pipe pile cofferdam.The model is proved to be correct by comparing the simulation results with the actual measurements.The results show that the cofferdam width has an appropriate range,too small and too large will cause the cofferdam deformation is too large.In this project,the reasonable width of cofferdam should be 3.5~4.5 m.The change of cofferdam width has little influence on the excavation deformation of cofferdam foundation.Considering the deformation of both sides of the steel pipe pile,the deformation of the tie rod is small when it is set at 0.8 m on the top of the cofferdam.