基于“CC工法”的顶管隧道施工地表变形规律分析与研究

Analysis and Research on Surface Deformation Law of Pipe Jacking Tunnel Constructed by Cut and Convert Method

为研究“CC工法”施工地表变形规律,依托实际项目,通过对施工过程中地表变形实际监测结果进行整理分析,采用线性回归分析的方法对数据进行拟合,总结本项目“CC工法”顶管隧道施工地表变形规律,将隧道上部覆土扰动分为3类,发现隧道掘进时地表变形呈先隆起后沉降的形态,最终地表总体表现为下沉形态;提出后掘隧道与先行隧道之间存在地表变形影响叠加区,对叠加区的范围和形态进行研究,并分析得出后掘隧道施工对先行隧道地表变形的影响程度;修正传统Peck沉降预测公式,引入地表损失量修正系数和沉降槽宽度修正系数,并验证修正系数的适用性。在此基础上总结影响“CC工法”顶管隧道施工地表变形的主要因素,并提出控制措施。

In this paper,the monitoring data of surface deformation during the construction of pipe jacking tunnel constructed by cut and convert(CC)method are summarized and analyzed;the linear regression analysis method is used to fit the data;the surface deformation law is summarized;the soil disturbance in the upper part of the tunnel is divided into 3 categories;and it is found that the surface deformation during tunneling shows a trend of settlement after uplift.And then the superposition zone of surface deformation affected by the tunnel and the preceding tunnel is proposed,of which the range and shape are described;and the influence degree of the tunnel construction on the surface deformation of the preceding tunnel is analyzed.Finally,the Peck settlement prediction formula is modified;the surface loss correction coefficient and the settlement groove width correction coefficient are introduced;and the applicability of the correction coefficient is verified.Meanwhile,the main factors affecting the surface deformation of the pipe jacking tunnel constructed by CC method are summarized,and the corresponding countermeasures are put forward.