At the end of July, TERRATEC celebrated the successful factory acceptance testing of the second of two new 4.66m diameter EPBMs that will be used by Italian contractor CMC di Ravenna on the 13.5km long Río Subterráneo a Lomas tunnel, in Buenos Aires, Argentina. The tunnel 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.
The tunnel is a key component of the multi-billion-dollar Agua Sur system that is currently being built by Argentina’s national water and sanitation company AySA. Financed by the Government and the Development Bank of Latin America (CAF), it is the country’s largest water infrastructure project in 40 years and will provide access to fresh water for 2.5 million inhabitants in the southern metropolitan area of Buenos Aires.
“AySA is confident that it has chosen the right contractor in CMC for this important project and we have witnessed the close relationship between CMC and its equipment supplier TERRATEC during this week of testing,” said AYSA Argentina Project Manager, Pablo Estigarrivia. “It fills us with confidence that this strong team will work together with the single goal of completing this project as rapidly as possible.”
The EPBMs have been designed to tackle the variable soft ground geology along the project alignment, which ranges from silts to sandy silts with some cobbles expected. Their high-torque soft ground cutterheads feature a spoke style design with a 49% opening ratio and cutting tools consisting of fixed and back-loading knife bits to ensure rapid advancement and minimum interventions.
The tunnel will be excavated at an average depth of 25m, beginning with an approximately 400m radius curve and continuing along an essentially straight alignment, reaching a maximum slope of +/- 2.0%. As the machines progress, they will install a precast concrete segmental lining ring consisting of six (four parallelograms and two keys) 250mm thick, 1400mm wide, segments.