Italian contractor Salini Impregilo has started work on a US$450 million tunnel project in Buenos Aires, part of the biggest public works in Argentina.
The 12 km tunnel will pass beneath the Riachuelo River, and is intended to return urban wastewater to the river, downstream of the planned Riachuelo treatment plant.
The scope of the work to be undertaken by Salini includes a 10.5 km tunnel, with an internal diameter of 3.8 m; a 50 m-deep load shaft at one end of the tunnel, as well as a return shaft at the opposite end; and a 1.5 km-long diffuser system, anchored in the river bed.
The tunnel will be dug at a depth of 40 m, in the bed of the river, using a double-shielded TBM with an internal diameter of 4.1 m.
In total, Salini anticipates moving around 550,000 m3 of earth and utilising 7,000 m3 of concrete on the project.
The tunnel development will enable the decontamination of the Riachuelo river basin, which has been affected by the industrial activities, including paper mills and tanneries, which have been dumping process by-products into it for many years.
Funding for the project – part of a wider initiative to promote sustainable development of the Matanza-Riachuelo catchment basin – has come from the World Bank.