Geotechnical study in Cabezón de Pisuerga

In Cabezón de Pisuerga, the geological substratum is dominated by limestones, dolomites and marbles, followed by compact gravels and sands, both suitable materials for foundations due to their high bearing capacity and resistance to differential settlement. The additional presence of gypsum, anhydrite and salts introduces an important factor to consider, as these materials can undergo dissolution and volume loss, particularly in areas where the aquifer is extensive and highly productive. Detailed characterisation is essential in order to select the foundation level correctly, avoiding zones with water or soft fines such as fine sands and silts.

Seismic activity in the area is high, with around 200 events over 30 years and a maximum magnitude (Mmax) of 4.7, so the structural design must incorporate earthquake-resistant calculation criteria. As it is an area with karstic development, it is essential to verify the possible existence of cavities or instances of dissolution before proceeding with any shallow or deep foundation, especially on calcareous and gypsum-rich ground, where the risk of subsidence or local collapse is notable. The main geotechnical constraint in Cabezón de Pisuerga stems from the combination of karstic risk and high seismicity; these aspects require an exhaustive geotechnical study to guarantee the safety and durability of the planned constructions.