Grove Vale Flood Alleviation Scheme

Clients: Total Pipeline Solutions, Southwark B.C. and Thames Water

Duration: 55 weeks

Location: East Dulwich, London

Description of works:

Michael Roarty, on behalf of Total Pipeline Solutions constructed 170m of 1.69m one pass tunnel, and 83m of 1.2m one pass tunnel online and associated shafts.

The tunnelling solution was adopted in favour of open—cut to minimise disruption on this heavily trafficked route into London.

The tunnels were driven online whilst coping with and maintaining a fluctuating ?ow in a live 1.4 x 0.75 brick egg combined sewer. Flows were managed using temporary pipes bracketed to the sides of the newly constructed sections of tunnel as excavation progressed.

As the existing sewer curved in parallel to the road, the 1.69 dia tunnel was driven on a series of curves requiring tapered segmental rings to follow the route of the existing sewer.

Major secondary diversions were required to facilitate the building of the shafts.

Due to the restricted working space at the shaft locations, the 1.2m dia tunnel was driven online, ln the same direction of flow with the tunnel invert lower than the culvert invert.

A number of timber headings were also driven to install sections of sewer downstream of the tunnels.

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