减沉桩在沉管隧道中应用的室内模型试验

Indoor Model Test of Reducing-settlement Piles in Application to Immersed Tube Tunnel

为了优化减沉桩在港珠澳大桥沉管隧道中的应用,根据相似理论,采用正交试验设计方案,设置了桩距、桩长、垫层厚度、有无桩帽4个影响因素和3个水平,完成了19组室内模型试验。借助于SPSS统计分析软件,采用方差分析对试验结果进行定性和定量分析。结果表明:桩长对沉降影响最为显著,对减沉效果的影响程度由大到小依次为桩长、桩距、垫层厚度、桩帽;各影响因素间的交互作用较小,皮尔逊相关系数显示在荷载较小时,桩距与沉降相关度较大,随着荷载的增大,桩长与沉降的相关度增强;减沉桩设计中桩长、桩距、垫层厚度均存在着合理的范围,桩帽可以取消。所得结论为港珠澳大桥沉管隧道的优化设计提供了理论依据,节省了工期和造价。

In order to optimize the application of reducing-settlement piles in immersed tube tunnel of Hong Kong-Zhuhai-Macao Bridge, 19 sets of model test in laboratory were completed according to the theory of similarity and orthogonal test design, which set the pile spacing, pile length, cushion thickness, pile cap as four influencing factors and three levels. With the help of statistics analysis software SPSS and variance analysis, qualitative and quantitative analysis of test results were performed. The results show that the greatest significant influence on the effect of reducing subsidence is pile length, followed by pile spacing, cushion thickness and pile caps and the interaction among various factors is small. When the load is relative low, Pearson correlation coefficient between the pile spacing and the settlement is relatively large. With the increase of the load, the relative degree of pile length and settlement enhances. In addition, there is rational range of pile spacing, pile length, cushion thickness for reducing-settlement pile design and pile caps can be canceled. The conclusion provides theoretical basis for the optimization design of Hong Kong-Zhuhai-Macao Bridge＇s immersed tube tunnel, which can shorten the construction period and reduce the cost.