Geotechnical study in Viana

Within the municipal term of Viana, the geotechnical substratum is predominantly dominated by sandstones, conglomerates and flysch, which provides a competent and relatively stable foundation for the construction of buildings. The frequent compact gravels and sands contribute to high permeability and facilitate the drainage of water, whilst the occasional presence of gypsum, anhydrite and salts warns of potential dissolution risks in certain areas. The groundwater level may be influenced by the existence of extensive and highly productive aquifers, which is why it is essential to characterise these horizons during the geotechnical study to ensure adequate bearing capacity and to select optimised foundation solutions.

As for geotechnical constraints, seismicity in Viana is very low, with only one significant event recorded every 30 years and with a low maximum magnitude (Mmax 3.1), which limits the influence of this factor on structural design. The non-clayey substratum eliminates the risk of soil expansivity, but special attention must be paid to the potential for karstification of the area before carrying out any foundation works, since the possible presence of cavities or dissolution constitutes the main geotechnical constraint for the proper development of the project.