超大直径泥水式盾构施工地层变形规律研究

Characteristics of Ground Deformation Induced by Large-Diameter Slurry Shield Construction

文章以南京市纬三路过江通道大直径双线盾构(φ14.5 m)工程为背景,结合现场监测数据,对超大直径泥水式盾构在砂、砂卵石地层中掘进引起的地表变形过程和分布规律进行分析。研究结果表明:盾构隧道地表纵向变形分为四个不同阶段,分别为隆起、快速沉降、缓慢沉降和最后稳定阶段;单线隧道施工地表变形可用Peck公式描述,拟合得到Vl值平均为1.856%,K值平均为0.423,整体呈现单峰状;双线隧道施工地表变形呈不对称双峰状,这是因为后建隧道的施工增加了地表最大沉降值以及沉降槽宽度,进而改变了沉降槽的形状;双线隧道施工地表变形可用双Peck公式进行描述,K值与隧道数量、施工历史情况无明显关联,Vl值与施工方法、质量控制及双线隧道施工顺序有关。研究结果可为类似工程提供指导及参考。

Based on the large-diameter （Ф14.5 m） double-tube river-passing shield tunnel at Weisalu of Nanjing city and on-site monitoring data acquired there, the process and distribution law of surface deformation induced by the construction of a large-diameter slurry shield in sand and sandy cobble strata was studied. The results indicate that vertical surface deformation of the shield tunnel includes four stages： heaving, rapid settlement, slow settlement and stabilization. Surface deformation of single-tube tunnel construction can be described by the Peck formula, with an average V1 value of 1.856% and K value of 0.423 by fitting a unimodel shape; Surface deformation of the doubletube tunnel is of a bimodal asymmetrical shape since the later tunnel construction causes the maximum surface settlement and the trough width to increase, thus the trough shape is changed. Surface deformation of the double-line tunnel can be described by a double Peck formula, and there is no obvious correlation between the K value and the number of tunnels and the construction history, and the V1 value is related to the construction method, quality management and construction procedure.