ABSTRACT

With reference to the construction conditions and features of metro tunnel, this paper analyzes the design features of double shield TBM and proposes key issues to be considered and settled when double shield TBM is used for metro tunnel construction, including small curve excavation, cutter head’s rock-breaking capacity, selection of backfill grouting technology and excavated material removal method, which all have a direct effect on the geological adaptability, tunnel lining quality and tunnelling performance of double shield TBM. This paper also studies the specific design and optimization scheme which includes the design of cutter head thick steel plate, stepped shield and monorail hoist. The successful performance of double shield TBM(φ6.5m) in Shenzhen metro project well proved its remarkable geological adaptability and advantages in mechanized construction(Max. daily advance 24m). Besides, this paper puts forward advice on the application of double shield TBM in the future engineering projects.