超深顶管工作井复合结构三维变形特性

3D Deformation Characteristics of Composite Structure in Ultra-Deep Pipe Jacking Working Well

以佛山市某超深埋电力隧道顶管工程为背景,采用现场监测和数值模拟相结合的方法,研究顶管工作井复合支护结构在施工过程中的变形规律。结果表明:数值模拟结果与实际监测值基本吻合;随着开挖阶段内支撑和内衬墙的施做,复合结构共同作用有效抑制了墙体水平位移向井内增大,下部土体开挖对上部墙体位移影响逐渐减小;而在顶进阶段,顶进反力作用范围内墙体发生向井外的位移,墙体向井外竖向和横向水平变形均随顶进反力的增大而增大;通过分析工作井后背墙体竖向和横向水平变形规律,表明整体变形为向井外“凸”出的曲面;最后建议距离顶进反力作用中心越近的内支撑设置间隔应越小,且截面尺寸应越大,以提高工作井结构的支护效率和整体稳定性。

Taking the pipe jacking project of an ultra-deep buried power tunnel in Foshan City as the background,the method of combining on-site monitoring and numerical simulation is used to study the deformation law of the composite support structure of the pipe jacking working well during the construction process.The results show that the numerical simulation results are basically consistent with the actual monitoring values;with the construction of the inner support and the lining wall in the excavation stage,the combined effect of the composite structure effectively restrains the horizontal displacement of the wall from increasing into the well.The influence of the displacement of the upper wall gradually decreases;while in the jacking stage,the wall moves out of the well within the range of the jacking reaction force,and the vertical and lateral horizontal deformation of the wall outside the well increases with the increase of the jacking reaction force;by analyzing the vertical and lateral horizontal deformation laws of the back wall of the working well,it is shown that the overall deformation is a curved surface that“bulges”out of the well;finally,it is suggested that the closer the distance to the action center of the jacking reaction force,the smaller the spacing between the inner supports,and the section size should be larger,in order to improve the support efficiency and overall stability of the working well structure.