电力隧道顶管工作井支护结构受力与变形实测分析

以佛山市某电力隧道顶管工程工作井(始发井)为例,对顶管工作井施工期间支护结构受力与变形情况进行现场监测。工作井施工期间监测数据表明:围护结构的变形具有明显的时空效应,工作井开挖期间长时间的暴露会导致地连墙深层水平位移增量变大、墙顶产生隆起以及内支撑轴力增大;内支撑的架设和底板的施工能够抑制地连墙水平位移向井内进一步增大,同时,也会使得其他内支撑轴力减小;拆除内支撑时,工作井围护结构整体水平位移变化幅度较大,靠近拆撑位置向井内位移,远离拆撑位置向井外位移,并且使得其他内支撑轴力增大;工作井支护结构“角部效应”明显,内支撑轴力和位移实测值均相对较小,设计偏于保守,应对设计方案进行优化。

Stress and Deformation Measurement Analysis of Retaining Structure of Pipe Jacking Shaft in Power Cable Tunnel

Taking the shaft (original well) of a power cable tunnel jacking project in Foshan as an example, the stress and deformation of the supporting structure during the construction of the shaft are monitored on site. The monitoring data during the construction of the shaft show that the deformation of the envelope structure has obvious space-time effects. Long-term exposure during the excavation of the shaft will cause the increase of the deep horizontal displacement of the diaphragm wall, and the uplift of the wall top and the internal axial force of support is increase; the erection of internal support and the construction of the bottom plate can inhibit the horizontal displacement of the ground connection wall from further increasing into the well, and at the same time, it will also reduce the axial force of other internal support supports; after the removal of the support, the overall level of the working shaft displacement amplitude envelope structure is large, and the displacement near the support removal position is to the inside of the well, and the displacement away from the support removal position is to the outside of the well, and such that the axial force is increased further within the support; the "corner effect" of the retaining structure of the shaft is obvious, The measured values of the internal support axial force and displacement are relatively small, and the design is conservative, and the design plan should be optimized.