上软下硬复合地层中盾构隧道管片受力变形性态研究

Research on Mechanical and Deformation Behaviors of Shield Tunnel Segment under the Condition of Upper-soft and Lower-hard Composite Stratum

以珠机市区至珠海机场地铁盾构工程为背景,采用MIDAS GTS NX建立了精细的三维管片模型,模拟上软下硬复合地层中盾构隧道管片的受力特征,并对衬砌环在岩层中的地层复合比进行参数分析。研究结果表明:上软下硬复合地层中,管片环拱底处几乎没有竖向位移,管片环拱顶及拱腰向内侧收敛,在设计时轴力取梁-弹簧法得到的最大轴力进行设计即可,弯矩的取值与地层复合比有关,在设计时应将地层复合比m=0.86当作关键工况予以考虑。

Taking the subway shield tunnel project of urban to airport in Zhuhai as the research background,this paper adopted finite element software MIDAS GTS NX to build 3D simulation model,which included the segment and bolt,to simulation the deformation and stress during the shield tunneling under the condition of upper-soft and lower-hard composite ground. And then analysis the influence of the ratio of soft soil in complex formation. The result shows that there are almost no vertical displacement at the crown,and the arch segment convergences to the inner side under the condition of upper-soft and lower-hard composite stratum. The axial force calculated by spring-beam method can be used in shield tunnel segment structure design,the bending moment of segment is related to the ratio of soft soil,m=0.86 should be taken into consideration when constructional design.