Geotechnical study in Fermoselle

In Fermoselle, the dominant substrate is made up of granites, gneisses and other igneous rocks, present in more than half of the municipality. These lithologies offer a high bearing capacity and a stable response for shallow foundations, although it is necessary to take account of the possible presence of joints or superficial weathering. Slates and schists occur only occasionally, providing local heterogeneity; however, in general terms, the risk of differential settlement is low provided that foundations do not bear on layers of weathered material or on zones that are highly fractured. The general impermeability of these materials limits infiltration and the depth of the shallow aquifers, which conditions the behaviour with respect to groundwater.

Seismicity in Fermoselle is very low, with only a single reported event in the last 30 years and a maximum magnitude of 1.9, so it does not constitute a relevant constraint for structural design. No evidence is identified of karst features or of gypsum or other soluble salts that could entail dissolution-related risks. The non-clayey substrate removes the concern regarding expansion potential, so the main aspect to consider in geotechnical studies is the correct characterisation of the degree of weathering and fracturing of the rocks, as well as ruling out the possibility of foundation support on saturated zones close to masses of water.