Estudio geotécnico in Larraga

In Larraga, the predominant ground is composed of sandstones, conglomerates and flysch, which usually provides an adequate bearing capacity for most buildings, enabling the execution of shallow foundations in most cases. Occasionally there are layers of limestones, dolomites, marbles, as well as fine sands, silts and compact gravels, which may influence the variability of soil compaction and permeability. Smaller proportions of gypsum, anhydrite and salts are also found; these materials may present dissolution-related problems. This aspect should be analysed if these layers are present, as they may compromise the long-term stability of the foundations.

The seismic setting in Larraga is one of moderate activity, with 21 events in the last 30 years and a maximum recorded magnitude of 2.3, indicating a low incidence of relevant seismic movements for conventional geotechnical design. Although hard materials predominate and no expansive clays are detected, the possible presence of carbonate materials requires particular attention to the phenomenon of karstification: before the start of any foundation work, it is essential to verify the existence of underground voids or dissolution zones, given their potential impact on ground stability and the durability of infrastructures. The main geotechnical constraint in Larraga is linked to the risk of karstification and, secondarily, to the localised presence of gypsum or soluble salts.