After 18 months of tunnelling underneath the capital, all six of the Channel Tunnel Rail Link (CTRL) Section 2 London Tunnels have been completed in the UK.
The 8.15m o.d. concrete lined tunnels totalled 35km in length and six TBMs were used to excavate ground conditions as varied as London Clay, dewatered Thanet Sand and chalks. With a total value of £540M, the tunnels were awarded as three distinct contracts.
Problems early in the life of the project related to the Stratford Box works, before tunnelling had even commenced, prompted the London Tunnels contractors, the Stratford Box contractor and the client to agree to an innovative commercial alliance. The alliance made collaboration easier and gave greater incentives for co-operation.
At a ceremony held in Stratford to mark the completion of tunnelling work, Transport Minister Tony McNulty said: “This incredible engineering achievement is a strong example of yet another transport success in London. The tunnels were completed on budget, on time and only 1mm wide of their final target.”
