拱北隧道大直径曲线管幕顶管顶力研究

Analysis on the jacking load of the curved pipe roof supporting the large diameter Gongbei tunnel

以我国在建港珠澳大桥拱北隧道管幕工程为例,研究长距离大直径曲线管幕的施工顶力。总结曲线顶管顶力的主要组成及影响因素;比较和分析中国和日本顶管规范的预测顶力和现场实测顶力的差异;推荐总顶力中迎面阻力的计算公式以及管壁单位摩阻力和摩擦因数的取值;基于力学平衡,推导分节曲线顶管顶力的计算公式。研究表明:泥浆润滑后钢管的管壁单位摩阻力和摩擦因数远小于以往研究中提供的混凝土管的管壁单位摩阻力和摩擦因数;推导的分节曲线顶管顶力公式的计算顶力和实测顶力吻合良好。研究结果可为类似的管幕工程以及供水、污水、供电、通信等管道的顶管设计和施工提供有益参考。

The load jacking the curved pipe roof supporting the large diameter Gongbei tunnel is analyzed. The major components and the impact factors of the jacking force along a curved alignment are discussed. The calculated jacking load based on the design codes of China and Japan is compared with the field measurement and the difference is investigated. The equation for estimating the front face resistance during slurry pipe jacking is recommended. The side frictional resistance and friction coefficient are suggested based on the field measurement to the pipe roof of the tunnel in Gongbei. A formulation for predicting the total jacking force for segmented curved pipe is developed based on the force equilibrium analysis. The analysis shows that the value of unit side resistance and the interface frictional coefficient of steel pipes with lubrication are significantly smaller than that of concrete pipes. The estimated jacking load using the equation derived in this study matches the field measurement well.