Geotechnical study in Grade

In Grado, the composition of the subsoil is dominated by limestones, dolomites and marbles, with a significant occurrence of shales and schists, while fine sands and silts appear only very sporadically. This predominance of carbonate rocks and metamorphic materials gives the ground a good bearing capacity, generally making it favourable for direct or shallow foundations, provided that the levels of alteration or weathering are suitable. The low permeability of the lithological formations limits infiltration, although shallow aquifers may form under certain local conditions.

From a geotechnical point of view, the seismicity in Grado is very low, with only two events over thirty years and a maximum magnitude of 1.9, so the seismic influence on structural design is practically non-existent. However, given the presence of limestones, there is a significant karst potential; therefore, it is essential to carry out specific investigations to rule out or characterise cavities before proceeding with the foundation. In addition, the non-argillaceous nature of the subsoil eliminates the risk of expansivity, with verification of karst development being the main determining factor for geotechnical studies in this municipality.