大直径空间C型曲线隧道顶管受力特性研究

Study on Force Characteristics of Jacked Pipes Under Construction of Large-Diameter and Spatially C-Shaped Curve Tunnels

以电力隧道为研究背景,采用现场实测的方法对大直径、长距离、空间C形曲线段隧道顶管顶进时管道受力特性进行研究分析。结果表明:管节在形成管-浆全接触的状态下,总推力与累计顶进距离关系不大,覆土深度对管壁接触压力有影响,但注浆压力占主导因素;环向钢筋应力以受压为主,管节内侧为压应力、外侧为拉应力,管节两端口直径缩小,呈现出“椭球状”;顶管横剖面上纵向钢筋正应力呈现出左部和上部受压、右部和底部受拉的应力状态,管节发生挠曲变形,管节中端向右凸出。因此,应合理布设钢筋并增大钢筋中的预应力,优化管道设计,提高管道性能,提高经济效益。

Taking power tunnels as research objects,the field measurement was conducted to study and analyze the force characteristics of jacked pipes under construction of a large-diameter,long-distance and spatially C-shaped curve.The results showed that:in the case of pipe sections in full contact with slurry,the total thrust had few relations with the cumulative jacked distances,and the thickness of overlying soil had an effect on the contact pressure of pipe walls,but the grouting pressure was the dominant factor;the stress in circumferential rebas was mainly in compression,pipe sections was in compression on the inside and in tension on the outside,and the diameters at the ends of pipe sections were compressed to“ellipsoid”;the longitudinal rebars in the left and upper parts of pipe sections were in compression,as well as the rebars in the right and lower parts of pipe sections were in tension,and the pipe sections were deflected under the action of bending moment and the middle part of the pipe sections deflected to the right.Thus,the reasonable distribution of rebars and increasing prestressed rebars could optimize the pipeline design,improve pipeline performances and economic benefits.