The Metro Line H in Buenos Aires, Argentina runs North-South, at the west side of the city's downtown area. The northbound extension of the line started in 2011 using conventional tunnelling methods and is close to completion. Two kilometers of tunnels and three cavern stations, namely Córdoba, Santa Fe y Las Heras stations, were excavated in stiff cemented silts and clays. Close to Santa Fe Station, the tunnel crossed two simple underground tunnels belonging to Line D. These tunnels remained operational and were not interrupted by the construction of the new tunnel, albeit the fact that the new tunnel is in direct contact with the foundations of the side walls of the old tunnel, and that it had no structural invert. In this paper, some design aspects, the logistics and construction issues of the project are described.
