The tunnel corresponding to the Hospitalet – Can Tunis Section of the High Speed Train Line connecting Madrid – Barcelona – French Border is one of the access tunnels to Barcelona. It is being used for freight trains connecting with the harbor.

It is a tunnel 2100 m long, which runs mainly under non urban soil but crossing important highways in Barcelona south entrance, such as Gran Via (8 lanes) and Ronda Litoral (6 lanes), and several important large size sewage infrastructures.

The construction procedure is the cut and cover tunneling method. The diaphragm walls were constructed using clamshell bucket equipments. Te cover is, a reinforced concrete partially precast flat slab. The tunnel is closed by a counter-vault in order to resist water pressure.

Geologically, it is located in the Llobregat river delta formation. Thus, the soil is basically sand with some silty-sand layers and a phreatic level 5 m under the surface. It was necessary to dewater the soil inside the enclosure.

Depending on the depth of the tunnel, variable due to the obstacles (highways and sewage infrastructures) to run underneath, it was necessary to use struts to stabilize the tunnel during construction, or to use the cover slab as a strut. In some sections permanent struts were also used.

Jet-grouting was also used for waterproofing some areas and also to stabilize the soil for a huge jacked box under the existing railway connecting Barcelona with Madrid with a length of 100 m