Estudio geotécnico in Alfajarín

In Alfajarín, geological formations of gypsum, anhydrite and salts predominate, followed by fine sands, silts and compact gravels. These materials give the subsoil a high degree of variability, increasing permeability and favouring the existence of extensive and productive aquifers. The presence of gypsum, anhydrite and salts, together with frequent layers of sands and silts, requires carrying out a detailed analysis of bearing capacity, as the dissolution of these salts poses a risk of subsidence or instability. It is recommended to found on compact gravels and sands wherever possible, avoiding direct support on soils that may be soluble.

Seismic activity in the municipality is notable, with 68 events in the last 30 years and a maximum magnitude of 4.8, which makes it necessary to incorporate earthquake-resistant design criteria into any structural project. In addition, the expansion of karst, due to the frequency of soluble materials, requires verifying the absence of cavities before the foundation is installed. Clay-related swelling is secondary, but its exact location must be confirmed in phases prior to the design of the foundations. The main geotechnical constraint in Alfajarín is the risk associated with the dissolution of gypsum and salts, together with control of the development of karstification.