By Ashley Karen
Terratec’s EPBM (earth pressure balance tunnel boring machine) Eva has succeeded in the site acceptance test and has begun boring the Río Subterráneo a Lomas tunnel in Buenos Aires, Argentina.
CMC di Ravenna, the Italian tunnel contractor is building a 13.5km tunnel that is going to supply drinking water from the freshly expanded General Belgrano Water Treatment Plant in Berna to the Lomas de Zamora.
The tunnel will be excavated by using two 4.66 Terratec EPBMs which have been designed to undertake the different geology along the project alignment. They have been delivered to the project in 2018 and 2019. Each machine has a high-torque soft ground cutterheads feature made of a spoke style design with a 49% opening ratio and cutting tools containing back-loading and fixed knife bits that are going to secure rapid advancement and minimum interventions.
Both boring machines are essential for the project to be received and launched from shafts. The tunnel will be dug at an average depth of 25m, using precast parts and segments with an inner diameter of 3.9m and an outer diameter of 4.4m and continuing along an essentially straight alignment, reaching a maximum slope of +/- 0.25%.
Four circular sectors that interconnected with each other in the bottom area have formed the first launch shaft. Nearly, the total width of the shaft is 12m, the length is 45m, and height is 25m.
Emilio Saraniero, the Terratec project manager explained that “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.”
The new Agua Sur System composes a series of major framework that contains the expansion of the General Belgrano Water Treatment Plant, 23km of water conveyance tunnel, a raw water intake, built-in two stages, 46km of pipe connections and two pump stations.
This project is Argentina’s largest water infrastructure project to be carried out over the last 40 years and is expected to take around 10 years to complete.
Once completed, the Agua Sur system will supply access to freshwater for 2.5M inhabitants in the southern metropolitan area of Buenos Aires.
