Research on Key Techniques of Shield Construction in Mixed Ground

In underground space development, the technique of shield tunnel construction of metro has been a great challenge when it comes to construction in mixed ground. Against this background, it is significant to research the technical features and the impact on surrounding environment caused by TBM. Based on the engineering case of Nanjing South Station to Lukou airport section of Nanjing Metro Line 6, this paper discusses the new shield tunneling technology "Ground Pass Shield Tunneling" (GPST) which has been first applied in China. In addition, the numerical analysis of the settlement control of a specific section is also discussed. From this case, suggestions about tunneling in mixed ground are presented to facilitate further utilization of shield method in similar ground conditions.