Geotechnical study in Grijota

In Grijota, the bedrock is dominated by limestones, dolomites and marbles, which provides suitable support for building thanks to its high bearing capacity and stable mechanical behaviour. Compact gravels and sands also appear significantly, offering similarly good levels of strength and drainage, whereas the incidence of gypsum, anhydrite and salts, although lower, requires attention, since these materials can cause dissolution phenomena under certain conditions. Given the lithological characteristics, the foundation selection must be assessed according to the uniformity of the ground and the depth at which less competent or soluble layers may occur.

Local seismicity can be characterised as notable, with 57 events over the last 30 years and a maximum magnitude of 4, which makes it necessary to incorporate specific seismic criteria into the structural design. In addition, the presence of karst formations in the carbonate substrata implies the need to examine ground stability and the possible existence of cavities or dissolutions before proceeding with the foundation. Although expansive clays are secondary and occur in environments that are less problematic from a climatic standpoint, the main geotechnical constraint in Grijota is the detailed verification of the karst and the areas with potential for soluble materials.