Geotechnical study in Boal

In the municipality of Boal, soils formed by slates and schists predominate, representing more than 73% of the substrate, while the presence of water bodies is occasional. This type of metamorphic material generally provides adequate bearing capacity, although the very low permeability of these formations may favour the existence of shallow aquifers in specific areas; therefore, it is essential to analyse the localised presence of water before defining the depth and foundation type. In general terms, shallow foundations are usually feasible provided that stability against potential landslides or surface weathering is controlled.

Seismicity in Boal is very low, with only 9 events recorded in the last 30 years and a maximum magnitude of 3.4, which does not constitute a relevant constraint for structural geotechnical design. In addition, the absence of clayey soils rules out expansivity risks, and there is no impact from karst processes in the municipality. As the main constraint, it is recommended to pay attention to the possible local presence of groundwater associated with impermeable formations, which could especially affect foundations close to shallow aquifers.