By Ashley Karen
TERRATEC has shared the successful advancement of the two dia. 4.66m Earth Pressure Balance Tunnel Boring Machines (EPBMs) currently operating in Buenos Aires, Argentina, for the Río Subterráneo a Lomas tunnel.
The first EPB TBM (S74) named “EVA”, begin its journey at the end of September 2020. Impressively, “EVA” finished the first drive, covering about 8km (7945m), by the end of 2022. The launch of its first machine was started during the Covid-19 pandemic. To complete this, TERRATEC and the Italian contractor CMC di Ravenna assured specific permission from different Argentina embassies in different countries, helping them to send a team of international technicians to Argentina.
CMC di Ravenna played a significant role in this work by founding an extensive organization, committing substantial resources to comply with governmental constraints, and successfully launching the first tunnel boring machine.
This impressive 13.5km tunnel is an essential component of the multi-billion-dollar Agua Sur system, currently being constructed by Argentina’s national water and sanitation company AySA. The Agua Sur system illustrates the country’s most extensive water infrastructure project in four decades and is poised to deliver fresh water access to 2.5 million inhabitants living in the southern metropolitan area of Buenos Aires.
The sister TBM, the dia. 4.66m TERRATEC EPBM (S73) named “JUANA” has been deployed by CMC di Ravenna for the last 5km of the tunnel project. The “JUANA” has accomplished an exceptional progress of 88 rings, covering a distance of 123.2m in just one week.
The TERRATEC EPBMs have been developed to manage the mixed soft ground geology along the project alignment, containing silts, sandy silts, and some cobbles. These TBMs are equipped with high-torque soft ground cutter heads featuring a spoke-style design boasting a 49% opening ratio and include cutting tools constituting multiple fixed and back-loading knife bits. This cutting-edge configuration secures rapid advancement and minimizes the necessity for interventions.
Both TERRATEC EPBMs were launched and received from shafts. The tunnel boring takes place at an average depth of 25m, starting with an about 400m radius curve before continuing along a mainly straight alignment, with a maximum slope of +/- 2.0%. As the TBMs advance, a precast concrete lining ring will be installed, which are incorporating six segments (four parallelograms and two keys) measuring 250mm thick and 1400mm wide each.
The first launch shaft is comprised of 4 interconnected circular sectors at the bottom area. This shaft pans about 45m in length, 12m in width, and 25m in height and serves as an integral starting point for tunneling operations.
The Agua Sur System is a complete infrastructure endeavor that contains various substantial works. These include establishing a raw water intake and developing the General Belgrano Water Treatment Plant to augment its water production capacity from the current maximum of 1,950,000m3 daily to an outstanding 2,950,000m3 daily.
Moreover, it includes building a 23km water conveyance tunnel, constructed in two stages, along with the two pump stations creation and a vast network of pipe connections spanning 46km. The ambitious project is expected to be done over a calculated timeframe of 10 years.
Further information is available here.
