White Papers
To Build a Tunnel Boring Machine: Why Assembly on Location is the Next Big Advancement
Is there a better way to build a Tunnel Boring Machine (TBM) that can benefit all parties involved? For decades TBMs have traditionally been assembled in factories, where the components are assembled and tested, then disassembled and shipped to the jobsite. Delivery of a machine can often be the critical path affecting project schedule, cost, manpower, and other factors. Onsite First Time Assembly (OFTA) has been developed and used on dozens of projects around the world to pass on cost and time benefits to contractors working on fast-paced projects with tight schedules. The use of OFTA is increasing, allowing for TBMs to be initially assembled at the jobsite, and cutting out extra shipping and disassembly steps. This paper will analyze the reasons for shop assembly vs. onsite assembly, determining the ultimate benefits and drawbacks of each. The paper will also draw quantitative comparisons in terms of time and money, as well as differences in carbon emissions, energy, and manpower requirements. The paper will conclude with a discussion on trends in TBM assembly today and where the future is headed when building these complex tunneling machines.
- Long Haul TBM: Use of a Rebuilt Main Beam Machine at the DigIndy Tunnel System in Indianapolis, IN
- Evaluating TBM Design and Performance, 30 Years Apart: The Lesotho Highlands Water Tunnel, Phase 1 and Phase 2
- Use of a Tunnel Boring Machine on Nepal’s First and Second TBM-Driven Tunnels
- Record-Setting Large Diameter Mixed Ground Tunneling in Turkey: The Eşme-Salihli Railway Tunnel
- Lessons Learned During Excavation of the Incredibly Challenging Yin Han Ji Wei Water Diversion Tunnel