The Plaza de las Glòries is located in a geologically complex area due to the formations in the Barcelona plain and the River Besòs delta.
From a geotechnical point of view, these are very different environments with the presence of over-consolidated clay in the first part of the structure and the presence of medium sand in the second part. Added to these features is the presence of the water table at a level which, at the lowest point, provides a water pressure equivalent to 18 m. The handling of the water table during the excavation also influenced the project’s activities since the position of the water level affected the stability of the interior excavation and was therefore on the critical path of the project.
Added to the inherent difficulties in underground work was the necessary exhaustive control required by an urban project. For this, the railway and metro tunnels and all the buildings within the highly affected perimeter were surveyed.
Also notable was the large quantity of utilities crossing the area of the tunnels’ alignment with the implications of propping, cutting and diverting and the need to keep most of them in service