箱涵施工对下方已运营地铁盾构隧道的影响分析

Influence of Box Culvert Construction on Running Metro Shield Tunnel Below

本文结合广州市某道路快速化工程中箱涵所在场地的勘察资料及下方地铁区间隧道结构设计情况,采用MIDAS-GTS数值分析软件,建立了该箱涵施工及使用对下方地铁区间隧道结构影响的三维数值分析模型,以及考虑实际荷载情况的隧道平面结构荷载法分析模型,分析评估了本箱涵开挖卸荷对下方既有地铁隧道变形和受力情况的影响。研究表明,该箱涵开挖施工及修筑回填期间,下方地铁区间隧道的最大水平及竖向位移均位于箱涵正下方的管片顶部,总体位移的最大值为4.74mm,小于地铁保护要求的总位移控制值。同时,下方盾构隧道结构的最大正弯矩值为11.8kN.m,最大负弯矩为-12.3kN·m,管片及接头的弯矩均远小于相应的弯矩控制值。由此可见,该箱涵施工及使用不会危及到下方地铁区间隧道的结构安全,不影响地铁的正常运营。

Combined with the geological survey information of one box culvert construction project and the design data of the running metro shield tunnel below the box culvert in Guangzhou, the MIDAS-GTS software is used to build 3D and 2D simulation models for analyzing the influence of box culvert construction on operating metro shield tunnel below. The research shows： during the period of soil excavation, structure construction and backfill, the maxi- mum of horizontal and vertical displacement of the running metro shield tunnel locates on the top of shield tunnel segment, which is just under the box culvert across. And the maximum total displacement value is 4.74mm, which is much smaller than the controlling total displacement value for metro protection. Meanwhile, the maximum sagging moment is 11.8 kN ·m, and the maximum hogging moment is -12.3 kN·m, which is also much smaller than the controlling bending moment value for metro protection. It can be concluded that the construction of the box culvert above will not endanger the metro shield tunnel below, and not affect the normal running of this metro line.