GERARD PAKES Consultants has carried out a feasibility study, detailed design and construction supervision of a 1.35m diameter trunk storm water sewer in Malmö, Sweden.
The 800m long Geijersgatan storm water sewer was built using a remote controlled tunnelling machine in a western suburb of the city. It is claimed to be the largest project ever carried out in Scandinavia using a remotely controlled tunnel boring machine.
The tunnel was built at the interface between soft glacial moraine deposits and the underlying limestone bedrock.
Materials encountered ranged from soft sands, through flints and boulders to hard limestone.
Groundwater was well above the tunnel crown so the specification called for a fully automatic, slurry operated, pressure balanced tunnelling system able to cut through rock.
Manchester-based Byzak Plant supplied equipment and personnel for the project. The alignment was split into four sections up to 235m long. Five shafts were sunk to build the tunnel. These were converted to access manholes when the tunnel was complete.
Tunnel lining comprised 320, 1.35m diameter steel banded pipes jacked in behind the machine. Manufactured by Hanson Pipes at Womborne in the West Midlands, each weighed more than 4t.
Client for the SEK17M (£1.3M) project was VA-Verket Malmö (the water and drainage authority). The project was completed on time and to budget. Tunnelling took six months.