Geotechnical study in Forest

In Selva, granite, gneiss and other igneous rocks predominate as the main geological formations, which provide excellent bearing capacity for shallow foundations due to their compactness and strength. At a smaller scale, sandstones, conglomerates and flysch occur, together with slates and schists, which may show a certain heterogeneity in their response. The occasional presence of gravels, compact sands and silts indicates the existence of granular soils suitable for bearing, while the generally low permeability of these materials minimises problems related to the migration of groundwater, although small superficial aquifers may exist.

Seismicity in Selva is high, with approximately 200 events over 30 years, although no high magnitudes are exceeded (Mmax 4.4), which makes it necessary to consider seismic criteria in structural design. On the other hand, the existence of karstic phenomena makes it essential to verify cavities or instabilities before founding, given the possible presence of underground voids associated with these environments, even over hard rocks. The non-clayey substrate rules out the risk of expansivity, so the most relevant geotechnical constraint in Selva corresponds to controlling karst features and ensuring an appropriate response to seismic actions.