复杂地层大断面圆形顶管结构设计

Structural Design of Large-Section Circular Pipe Jacking in Complex Strata

摘要:

随着城市建设向纵深推进，非开挖工艺中的大直径顶管在综合管廊等工程中应用广泛，但复杂地层给顶管结构设计带来挑战，当前相关规范与研究多基于均匀地层，对复杂不均匀地层的设计研究较为欠缺。在福州江南片区综合管廊工程中，场地具有“上软下硬”的复杂地质特征，以此项目为背景，采用PLAXIS有限元软件，分析不同入岩深度和岩层倾角对顶管结构受力与变形的影响。研究结果表明：顶管进入岩层 120°支承角范围时，拱效应发挥最佳，结构受力最有利；且入岩深度的改变对结构的内力影响较大，考虑不周会对结构的安全造成影响。岩层倾斜会导致结构弯矩分布不对称，结构向岩层低处变形趋势明显。

Abstract:

With the in-depth advancement of urban construction, large-diameter pipe jacking in trenchless technologies has been widely applied in projects such as utility tunnels. However, the complex stratum conditions pose challenges to the structural design of pipe jacking. Currently, the relevant specifications and researches are mostly based on homogeneous stratum, and there is a lack of research on design of complex heterogeneous stratum. In the utility tunnel project in the Jiangnan area of Fuzhou, the site features the complex "soft-over-hard" geological characteristics. Based on this project, the PLAXIS finite element software is adopted to analyze the impacts of different rock penetration depths and rock stratum dip angles on the stress and deformation of the pipe jacking structure. The research results show that when the pipe jacking enters the range of the 120° bearing angle of the rock stratum, the arching effect performs optimally and the structural stress condition is the most favorable. In addition, the change in rock penetration depth exerts a significant influence on the internal forces of the structure, and inadequate consideration of this factor will threaten the structural safety. The inclination of the rock stratum will lead to asymmetric distribution of structural bending moments, and the deformation trend of the structure towards the lower part of the rock stratum is obvious.