Geotechnical study in Allo

In Allo, the geological subsoil is dominated by formations of sandstones, conglomerates and flysch—materials that exhibit good bearing capacity and, in most cases, favour solutions involving direct foundation. The occasional presence of fine sands, silts, gypsum, anhydrite and salts introduces greater heterogeneity into the subsoil profiles; therefore, detailed characterisation is recommended to identify possible zones with lower cohesion or with a risk of dissolution. Gravels, compact sands and limestones, dolomites and marbles also provide good conditions for foundation, although the identification of groundwater bodies must be considered to avoid drainage problems or undermining.

Seismic activity is very low, with a maximum recorded magnitude of 1.5, so the influence of seismicity on structural design is minimal. Given the occasional presence of gypsum, salts and anhydrite, there is potential risk of dissolution that may affect the long-term stability of foundations, mainly in areas where these materials are locally dominant. The non-clayey subsoil rules out the possibility of problems related to expansive clays. In addition, since karst development is possible, verification of the karst is essential before designing any foundation; this is the main geotechnical constraint in the municipality.