Two more sites on the central section of Tideway have completed their connection tunnels and exposed the segments lining the main super sewer tunnel deep below the River Thames.
Chelsea Embankment Foreshore and Heathwall Pumping Station excavated their connection tunnels using a sprayed concrete lining (SCL) method. This method requires the team to excavate forward 1m at a time before sprayed liquid concrete onto the exposed walls of the tunnel.
Across the road from the Royal Hospital Chelsea, the Chelsea Embankment team began digging the 55m-long tunnel from the base of the shaft which is located within the site’s cofferdam, a dry working area built out into the river. Construction of the tunnel has been completed since the site resumed working following the pause in response to the Coronavirus outbreak, meaning the team had to factor in working under the new safety guidelines as they progressed.
At Heathwall Pumping Station, a 43m-long tunnel was excavated from the deeper of two shafts on site. Completion of the tunnel brings to an end almost 14 months of constant excavation, which included the two shafts, a connection culvert - linking the two shafts - and the new connection tunnel out to the main tunnel.
The teams will now turn their attention to waterproofing the tunnels before they commence the secondary lining.