Agua Sur Argentina underway 01 Mar 2021

Excavation has started on the Río Subterráneo a Lomas tunnel in Buenos Aires, Argentina for Italian contractor CMC di Ravenna after the first of two Terratec 4.66m diameter EPBMs chosen for the project passed its site acceptance test and started on the drive.

Work has started on the 13.5km Agua Sur water tunnel

The 13.5km long tunnel will carry drinking water from the newly expanded General Belgrano water treatment plant in the city of Bernal in the Quilmes district to the city of Lomas de Zamora.

The Terratec EPBMs are designed to undertake the variable geology expected along the alignment. They have been equipped with high-torque soft ground cutterheads with a spoke style design and a 49% opening ratio. Cutting tools consisting of fixed and back-loading knife bits will ensure rapid advancement and minimum interventions. Each TBM cutterhead has eight hydraulic motors with a total power of 792 kW.

The two TBMs will be launched and received from shafts and follow a mostly straight alignment, reaching a maximum slope of +/- 0.25%. The tunnel will be excavated at an average depth of 25m, using precast segments with 4.4m o.d. and 3.9m i.d.

The first launch shaft is 45m long x 12m wide x 25m deep and composed of four circular sectors interconnected at the base.

Terratec EPBMs with high-torque soft ground cutterheads

“As the machines are launched from a shaft, we have made full use of a modular design and umbilical launching system to work in the confined space, which is why a hydraulic drive solution was chosen,” said Emilio Saraniero, Terratec Project Manager.

The new Agua Sur System includes a raw water intake, the expansion of the General Belgrano Water Treatment Plant, which will increase its water production capacity from a current maximum of 1,950,000m³ per day to 2,950,000m³ per day. The 23km water conveyance tunnel will be built in two stages and consist of two pump stations and 46km of pipe connections. The whole project is expected to complete in 10 years.

A cutterhead lowering ceremony was held in June 2020 and attended by Argentine President Alberto Fernández, and a number of government officials and representatives from Argentina national water and sanitation company AySA and CMC di Ravenna.

It is the largest water infrastructure project to be carried out in Argentina during the last 40 years.