Britain’s Mott MacDonald, in association with South African engineering firm, GMKS, has won an assignment to advise on the tunnelling options for a 4.5m dia, 500m utility services tunnel and a people mover tunnel in Durban, South Africa.
The contract was awarded by Durban’s eThekwini Municipality Water and Sanitation department.
The tunnels will replace an existing immersed tube tunnel that will be demolished as part of a US$143M harbour expansion that will take place in 2006. Dredging works for the project, which involves widening and deepening the harbour, will cut through the existing tunnel. Consequently the longer and deeper replacement tunnel has to be built before the harbour expansion can begin – resulting in a tight design and construction schedule. A separate underground people mover system to transport people from one side of the harbour to the other is also planned.
Mott MacDonald will provide technical assistance on the various tunnelling options as well as advise on the people mover options. The tunnels are expected to be built in 2005 through river deposits and sandy clay which would suit either slurry or EPB tunnel machines, which have not previously been used in southern Africa.
