Geotechnical study in Rosselló

In Rosselló, the subsoil is dominated by sandstones, conglomerates and flysch, which represent around 55% of the ground, supplemented by smaller proportions of fine sands, silts and compact gravels. These lithologies impart good bearing capacity and generally allow for shallow foundations; however, the low permeability of these materials may affect the disposal of groundwater and the aggressiveness of the environment towards concrete and structural steel. It is advisable to study the possible local presence of thin layers of silts or loose sands in order to avoid differential settlement or liquefaction problems in exceptional situations.

Seismicity in Rosselló is very low, with only 3 events over the last 30 years and a low maximum magnitude, so seismic risk does not represent a significant limitation for geotechnical design. There are no karst phenomena in the area and the risk associated with the swelling (expansivity) of clays is subordinate, being linked only to specific hotspots or particular climatic conditions. Consequently, the main geotechnical constraint is related to the heterogeneity of the formations and the local characterisation of each site, rather than to risks of seismicity or expansivity.