Rail Tunnel to T1 of Barcelona-El Prat Airport

The project was designed to connect the new Terminal 1 of the Barcelona—El Prat International Airport with the Barcelona suburban railway network. Terminal 1 was put into service in 2009 to increase the airport's passenger capacity. The new tunnel will provide a public transport alternative between Terminal 1 and the city center and the entire subway network. It is expected to serve up to 9 million passengers every year.

The new railway access runs along a total of 4,495 meters and includes a tunnel totaling 3,385 meters. The tunnel boring machine (type EPB named “Gala”) drilled 3,048 meters of the total tunnel length. The rest of the tunnel was excavated by the cut-and-cover method. The project also included the construction of two new stations at Airport Terminals 1 and 2.

The Barcelona – El Prat International Airport is located over the soft soil of the Llobregat Delta. Excavating the tunnel at a depth of 25.8 meters with an enormous tunnel boring machine with a 10.6-meter diameter through the ground with low bearing capacity was challenging. The challenge escalated as the tunnel crossed under Hwy C31, the Airport Terminal 2 facilities, and the Airport's main runway, which was kept in service throughout all the construction works.

Monitoring Solution

The instrumentation and monitoring solution adopted controlled ground deformations and groundwater variations in the area to avoid affecting the infrastructure under construction and the existing infrastructure, including the airport runways. Monitoring instrumentation was critical as the tunnel was excavated quite deep in the ground with low bearing capacity and a high water table. Encardio-rite was the selected supplier of the monitoring instruments deployed in the project.

Instruments Used