Technical specifications

Scope of works:

• Twin-tube road tunnel under the River Thames, 2 x 1,400 m long,
• internal diameter 10.66 m, external diameter 11.45 m
• Access ramps, 600 m in length
• 8 cross-passages
• Service buildings at both tunnel portals
• 1 new footbridge
• 1 new overbridge for the southbound carriageway of the Blackwall Tunnel

Construction method:

• TBM tunnelling using an EPB TBM, 2 x 1,120 m
• TBM diameter 11.8 m,
• Twith steel fibre reinforced segmental lining,
• Construction of cross-passages using ground freezing and sprayed concrete lining including rebar reinforded concrete secondary lining, 300 m cut and cover tunnel

Geology

• London Clay, dense sands of the Lambeth Group, dense gravels of the Harwich Formation, River Terrace Deposits