Geotechnical study in Pastriz

In the municipality of Pastriz, soils predominantly comprise fine sands and silts, together with a significant presence of gravels and compact sands. These lithologies, in general, provide good conditions for bearing capacity and offer a wide range of foundation options, making it possible to choose both shallow and deep solutions, depending on the project requirements. However, areas with gypsum, anhydrite and salts occur in a minor proportion, which calls for special attention due to the potential risk of dissolution and its possible consequences for foundation stability. In addition, the existence of extensive masses of water indicates extensive and highly productive aquifers, an aspect to be taken into account both during excavation and in protection against groundwater.

The seismic activity of Pastriz is classified as notable, with 68 events recorded over 30 years and a maximum value (Mmax) of 4.8; this level of seismicity makes it necessary to consider seismic actions in structural design in accordance with current regulations. There is potential risk associated with karstification, so it is essential to verify the presence of cavities or dissolutions before proceeding with any foundation. As regards expansivity, the incidence of expansive clays is subordinate and mainly confined to climatic environments without a significant water deficit, which partially reduces its impact, although it does not eliminate it completely. The most important overall constraint, therefore, is the dual check against karst-related risks and the influence of seismicity.