Factors of Scale Planning Design and TBM Considerations for Large Diameter Bored Tunnels

Abstract

Large diameter TBM driven tunnels are becoming ever more frequent options for consideration in achieving owners requirements. This paper will look specifically at the challenges that large diameter tunneling has from three aspects. Planning, Design and TBM requirements. Factors of “Scale” when compared to the more standard TBM projects is the common denominator, yet in each phase of the project this common element presents unique challenges to be overcome. The paper will set out these unique challenges and seek to inform future planning efforts through experiences on some of the world’s largest TBM driven tunnels.