The project, named Saliemelav, contributes to guaranteeing the execution of vertical tunnels on grounds with complex geological characteristics, especially in city environments.
During the works of the emergency exits in the tunnel Sants-La Sagrera, whose depth varies between 40 and 49 metres in the middle of Barcelona’s city centre, the presence of gravel and sand in the excavation areas required the search of an alternative to ensure their execution without risk, something that was possible thanks to a monitoring plan of the auscultation of the ground with real-time readings.
Sando has executed a double crown of drying columns of jet grouting to improve the excavation of the vertical tunnels, which has served as a continuous barrier, stable and safe, previous to the drilling through vertical tunnel boring machine.
It has also carried out a wall of secant piles of mortar with a crown perimeter depth until the totality of the future excavation of the well in order to improve the excavatable condition of the vertical tunnels.
This preliminary treatment of the ground as well as the real-time auscultation system, which issues a warning in case of detection of movement in any of the actions, have given greater stability to the land and the nearby buildings.