By lyndamyer
Following completion of the 1.1km southbound drive from Newham and reaching the rotation chamber in Greenwich by TBM Jill on February 15, the first bore on London’s Silvertown Tunnel has been completed.
In order to excavate the second tunnel, currently, the TBM is due to be rotated in pieces within the 40m rotation chamber, before commencing its journey back beneath the River Thames to the Silvertown site in Newham.
The main target of the rotation process will be sections of the TBM being placed on nitrogen skates in the chamber, while the individual sections of the TBM, including the 1,200T cutterhead, are going to be spun 180 degrees inside the shaft before being reassembled and reconfigured.
The estimated date for completion of the second bore is end of the summer.
As the largest one that ever used in the UK, the 82m-long Herrenknecht TBM’s cutterhead diameter is 11.91m, whereas September 2022 was the date of commissioning this machine and its daily average advance is 18m.
Due to damage of half of the conveyor belt, the tunneling process was halted less than three weeks after the TBM launch in previous year.
According to Riverlinx CJV project director Juan Angel Martinez: “The solutions being implemented on the project were pioneering for the UK market. We continue to be committed to completing the project expertly in the most efficient, sustainable way and to the highest level of safety and quality.”
In the meantime, the process of piling and concrete pours for the foundations for the cut and cover sections of the tunnel, as well as the portal entrances, are undergoing at the two tunnel portals.
Linking Newham to the Greenwich Peninsula and easing congestion at the Blackwall Tunnel, the twin-bore Silvertown Tunnel is slated to be inaugurated in 2025.
While the Riverlinx CJV, a joint venture contracted by Transport for London (TfL) and Riverlinx comprising BAM Nuttall, Ferrovial Construction and SK ecoplant will deliver this project, it is being delivered through a design, build, finance, operate and maintain contract (25 years in length). The majority of the funding is from private finance, which has been specifically raised for the scheme.
Although TfL’s forecast was a £1m increase for the Silvertown Tunnel in December 2022, currently it estimated that the project is running £13m over budget. An investment program report, to be presented to a meeting of TfL’s Programs and Investment Committee on March 1, says inflationary pressures have increased the estimated final cost to £186m.
Additionally, the report indicates that considering the shortages of skilled labor and materials supply problems, the date of inaugurating this project has also been postponed from April to June 2025.
