不同隔离措施在阻隔盾构施工引起地层变形试验研究

以京张高铁清华园大直径泥水盾构隧道工程为背景,重点探究盾构掘进过程中竖向隔离措施对于地层变形传播的阻隔特征。实测3种竖向隔离结构包括钻孔灌注桩、复合锚杆桩及门型墩的位移及其影响下的地层变形,同时提出衡量隔离措施对地层变形阻隔程度的判别指标,依据此指标发现,门型墩的隔离效果最优、钻孔灌注桩的隔离效果次之、复合锚杆桩的隔离效果最差,但三者的隔离效果的差别并不很明显。同时采用数值方法对隔离措施的隔离效应进行模拟,得出同样类似的结论。本文的研究可以为类似工程中隔离措施的选择提供借鉴,考虑到经济的适用性要求,一般采用复合锚杆桩足以阻隔变形。

Application of Cast-in-place Piles in Blocking Deformation Caused by Shield Tunneling

Based on the Tsinghuayuan Tunnel Project of Beijing-Zhangjiakou High-speed Railway, this paper focuses on the barrier characteristics of vertical isolation measures against formation deformation propagation during shield tunneling. The displacement of three vertical isolation structures including bored piles, composite anchor piles and portal piers and the deformation of the stratum under the influence of the piles are measured. At the same time, the discriminative index for measuring the degree of blocking of the formation deformation is proposed. With this index, the isolation effect of the portal pier is found to be the best, that of the bored pile the second, and that of the composite anchor pile the most ineffective, but the difference of the isolation effect of the three is not obvious. At the same time, the numerical method is used to simulate the isolation effect of the isolation measures, and similar conclusions are drawn. The research in this paper can provide reference for the selection of isolation measures in similar projects. Considering the economic applicability requirements, composite anchor piles are generally used to block the deformation.