Fabrication of a purpose-designed cradle to support the TBM – ‘Alice’ before she commenced tunnel boring.
Key Elements:
- Cradle overall was approximately 18m long and 10m wide.
- Made in 4 sections for transport, then bolted together on site.
- Heavy plate Welded beams to support TBM.
- Full penetration butt welds of diagonal support to the frame.
- Rail to spread the load of TBM and allow it to jack off.
Challenges:
- Matching up 4 different fabricated sections - trialled assembly in the shop.
- Heavy plate welded beam FPBW to frame at an acute angle
- Unique rail profile to support TBM.
- Structural bolted splice joints.
- Structure to take unusual loads of TBM jacking forward into the tunnel.
