By Lynda Myer
While the current works on Transport for London’s (TfL) Silvertown Tunnel are advancing well, the contractors are waiting for the excavation process to start.
Herrenknecht factory in Germany is responsible for manufacturing the Silvertown tunnel boring machine (TBM). According to the Riverlinx consortium, the project’s contractor’s statement: “We are getting ready to welcome the TBM to the site so we can reassemble it here early next year, ready to launch in the spring of 2022.”
The intended TBM, which is almost 82m long and1,800t weight, is due to have a cutter face of almost 12m.
The aim is connecting Silvertown to the Greenwich Peninsula via two tunnels by Silvertown Tunnel.
While a single TBM is going to dig both tunnels, it will complete one of the tunnels before turning around to complete the second.
“It won’t have an easy job as the geology of this part of London is stiff clay layers and boulders. It will excavate nearly 600,000t of material to form the tunnel. This material will be extracted by barges along the river to keep construction traffic to a minimum during the project,” adds information available on the Riverlinx consortium’s virtual exhibition.
Enabling works within the Silvertown Site (North Thames) continue with all of the primary and secondary piles that form the ‘Launch Chamber’ now complete.
In total six concrete counterforts for the launch chamber is due to install and currently five of them have been completed and work continues on the last one which will be finished this weekend.
The following stage after completing the piling of the Launch Chamber near, is to dig among the pile shafts and create the subsurface Launch Chamber for the TBM.
Although the river wall sheet piling works have currently started and are advancing well at a mean rate of 8 piles daily, the method of piling adopted at the river wall requires an A-Frame rig to be assembled and then dissembled every 16 sheet piles.
Due to placing these activities immediately above the new tunnel route, the new river wall will provide extra strength to the available embankment. The determined date for completion of these works is spring 2022 before commencing the tunneling process.
