Barhale, the UK-based infrastructure specialist, designed an advanced tunnel shield for a 215m pipe jack that has linked to the main Tideway Tunnel under London’s River Thames.
By building 30m deep into the London Clay, the 2.5m-diameter pipe links the freshly built CSO drop shaft located at Barn Elms Sports Centre to the main Tideway Tunnel, and is going to be finished with a 2.2m internal-diameter secondary lining.
Since difficult conditions were faced in the first stages of the pipe jack, the project needed an advanced solution. These things resulted in damaging some of the reinforced concrete jacking pipes as they were pushed in behind an open backhoe-type TEM (tunnel excavator machine).
Barhale Tunnelling Operations Manager, Frank Green stated: “With the support of the project team, we developed an innovative solution to help us quickly identify and replace any cracked pipes. It saw us design a bespoke recovery shield which we were able to manufacture in-house through our fabrication arm BCS.”
He also asserted: “The recovery shield not only enabled the damaged tunnel [sections] to be replaced but also provided access to the TEM face to enable repairs and enhancements to be conducted. Additionally, the purpose-made TEM was designed to allow complete dismantling at the end of the blind tunnel drive to allow the final connection to the main tunnel to be completed.”
The work was performed as part of the programme to construct the West Putney Storm Relief Combined Sewer Overflow at Barn Elms in Richmond, West London.
The BAM Nuttall Morgan Sindall Balfour Beatty (BMB) joint venture has awarded the main civils package to Barhale. It is delivering the 7km west section of the 25km Tideway Tunnel.