Geotechnical study in Alfarb

In Alfarb, deposits of gravel and compact sands predominate, offering very good bearing capacity and stability conditions for shallow foundations, especially when they are well graded and consolidated. Limestone, dolomite and marble formations are also present, which gives a competent behaviour but requires analysing the presence of discontinuities. The occasional occurrence of gypsum, anhydrite and salts implies a risk of dissolution processes, in addition to the localised presence of hard clays and marls. These features make a detailed assessment of the bearing stratum and the precise identification of the bearing level essential, avoiding those where soluble or insufficiently competent materials predominate.

Seismicity in Alfarb is very low, with only 2 recorded events over 30 years and a maximum magnitude of 1,7, so the seismic influence on structural design is minimal. However, the potential presence of karst in calcareous materials makes it essential to verify this phenomenon before defining the foundation solution, due to the possible development of voids and sinkholes. The expansiveness of the clays is considered subordinate and limited by the local climate, thereby reducing its impact. Overall, the main geotechnical condition to be controlled in Alfarb is verification of karst and the assessment of dissolution-related risks in the presence of gypsum and salts.