Terratec has announced that the 4.66m diameter EPBM ‘Eva’ has passed its site acceptance test and is currently being driven by Italian tunnel contractor CMC di Ravenna on the 13.5km long Río Subterráneo a Lomas tunnel, in Buenos Aires, Argentina.
The tunnel that will carry drinking water from the newly expanded General Belgrano Water Treatment Plant, in the city of Bernal (Quilmes district), to the city of Lomas de Zamora.
In June 2020, a cutterhead lowering ceremony was held in the presence of Argentina’s President, Alberto Fernández, as well as numerous government officials and representatives from Argentina’s national water and sanitation company AySA and CMC di Ravenna.
The tunnel project is significant as it is Argentina’s largest water infrastructure project to be carried out over the last 40 years. Being the main element of the Agua Sur system. The new system will provide access to freshwater for 2.5 million inhabitants in the southern metropolitan area of Buenos Aires.
Two Terratec EPBMs will drive the tunnel. Both 4.66m diameter machines are designed to undertake the variable geology along the project alignment. The TBMs high-torque soft ground cutterheads feature with a spoke style design with a 49% opening ratio and cutting tools consisting of fixed and back-loading knife bits that will ensure rapid advancement and minimum interventions.
Each TBM cutter head has eight hydraulic motors with a total a power of 792kW. The project requires the two boring machines to be launched and received from shafts. The tunnel will be mined at an average depth of 25m, using precast segments with an outer diameter of 4.4m and an inner diameter of 3.9m and continuing along an essentially straight alignment, reaching a maximum slope of +/- 0.25%.
The first launch shaft is composed by 4 circular sectors that interconnected with each other in the bottom area. The total length of the shaft is around 45m, width 12m and around 25m high.
“The fact the machines are launched from a shaft has required us to make full use of a modular design and umbilical launching system to work in the confined space, this is why a hydraulic drive solution was chosen” explained Emilio Saraniero, TERRATEC Project Manager.
The new Agua Sur System forms a series of major framework that includes a raw water intake, the expansion of theGeneral 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 – 23km of water conveyance tunnel (built-in two stages), two pump stations and 46km of pipe connections. The whole project is anticipated to take approximately 10 years to complete.